In the fight with Amazo, Sherloque comments that because the android absorbed the powers of Supergirl and Superman, it is invulnerable and thus cannot be penetrated to deliver the virus, and Iris makes a very specific comment about Amazo inheriting the heroes' weaknesses. To me, that was pointing to using a kryptonite arrow, but the scene doesn't clearly establish this. That, and the rather clumsy way the scene tried to make Barry grim and gruff like Oliver made me wish the fight had ended a little differently.

The normal notes: Characters, environments, etc. belong to DC Comics and the CW. This is written purely for fun. Thanks for giving my story a chance.

…

[Alternate scene, Central City, beginning after Barry grapples to the rooftop during the fight with Amazo and while the S.T.A.R. Labs team is discussing how to take it down (The Flash 5x09, "Elseworlds, Part 1")]

"Look, if Amazo inherited all of their strengths, then maybe it inherited their weaknesses too," Iris postulated over their comms.

Throughout this entire mess of alternate reality, Barry's mind had been a swamp, his own life and memories swimming around confusingly with the past experiences and knowledge of Oliver Queen. Iris's comment, however, shot through his thoughts in a moment of clarity, an inspiration drawing solidly on his "life" as the Green Arrow. He twisted his head, checking his quiver to be sure, before hardening his resolve.

"Okay," he grunted into his own comms, drawing a very specific arrow from his back, one with a thick, dull tip. "Oliver, once you've drawn Amazo back here, knock out its legs. Superman and Supergirl will catch it and pin it down so you can cancel its phasing."

"Copy that," Oliver acknowledged.

"Cisco, get ready to breach in and inject the virus."

"How will I know when?" Cisco asked, confused.

"You'll know," Barry replied curtly.

From his vantage point on the rooftop, Barry watched Kara and Clark position themselves just as the familiar streaks of superspeed appeared far in the distance. With his connection to the Speed Force lost, he couldn't physically see what was about to happen next, but his mind's eye, informed by his experience as the Flash and his instincts as the Green Arrow, was more than enough. Fitting his arrow to the drawstring of his bow as though he'd been doing it all his life, Barry pulled back and aimed for where he knew Amazo would be.

As soon as he was in range, Oliver dropped out of his superspeed and slid to a crouch, bracing himself against the ground as Amazo ran right over him, its legs getting swept out from beneath it. Before it had a chance to adjust or even hit the ground, the Kryptonians sped forward and grabbed one arm each, allowing Oliver to come up behind and put it in a headlock. Between Oliver's phasing and the superstrength of the cousins, the three of them were able to hold down the android in the exact spot where Barry was aiming.

This was the moment. Barry knew exactly what he needed to do and could even feel Oliver's training guiding him, but unexpectedly, his hand trembled slightly on the bowstring. This is crazy, the Flash side of his mind complained. I can't do this. This shot is too important. I'm not an archer! His aim began to waver as he struggled to get his hand under control.

"Shoot!" Iris yelled through his earpiece.

Once again, the sound of Iris's voice lanced through Barry, a reminder of what he fought for every day as a hero. Nearly every time I learn a lesson, it comes with a painful memory. Oliver's words back in Smallville echoed in his ears, and suddenly he saw Amazo for what it was, for what he knew the former Starling City vigilante would see it as.

A threat.

The android had absorbed the abilities of every powered individual it had encountered, making it, among other things, a speedster. Searing memories sped through his brain, from the screams of his mother as the Reverse Flash murdered her, to the sight of his father standing tall as Zoom skewered him from behind, to Wally's anguish as he lay on the bed in S.T.A.R. Labs with a kneecap Savitar had crushed before kidnapping Iris. Year after year, evil speedsters had come after his home and the people he cared about, had taken things that he could never get back.

His hand stopped trembling, and his aim reset. "Never again," Barry whispered to himself, and released the arrow.

…

Time slowed down for Oliver as he watched the arrow approach. Though this alternate reality had robbed him of the muscle memory that enabled him to shoot a bow, he had plenty of experience to know that Barry's shot would land true. The real problem was that the arrow wasn't going to do any damage. Even from a distance, it was clear the arrow's tip was blunt and would bounce off Amazo, if it didn't outright disintegrate against the indestructible qualities the robot had inherited from the Supers. He couldn't understand why Barry had chosen such a useless projectile.

Then, through his sped-up perceptions, Oliver saw the top layer of the arrow strip away in midair, and he realized he had submerged himself into Barry's way of thinking more than he'd realized, forgetting his old tricks.

By the time the arrow reached the android, its green, glowing, kryptonite tip had revealed itself underneath its lead casing. There was a fraction of a second when Oliver registered panic on the faces of Kara and Clark, but that was all the time anyone had to react before the arrow plunged itself into Amazo's chest. A strange, mechanical sound that could only be assumed to be the android expressing pain rang in all their ears as a sickly green glow spread in lines across the android's body like radiating veins. Kara and Clark both lurched away from the robot, likely driven by instinct to get away from kryptonite, and Oliver braced himself to attempt holding down Amazo alone. However, the arrow had done its work, and the android fell to its knees, seemingly unable to access any of its abilities.

In that instant, a swirl of blue and white signaling the opening of a breach appeared in front of the robot, and Cisco leaped through. Without even taking two steps, he jammed a device into Amazo's head, injecting the virus. The metallic body of the android vibrated for a few seconds, and then the lights in its eyes went out, followed by the torso forcibly ejecting each appendage and turning the monstrosity into a pile of parts. "Booyakasha!" Cisco cheered, pumping both his fists.

"Good job, Cisco," Oliver said. Mindful of their allies, he then quickly yanked the still-glowing arrow out of the wreckage and shoved it into Cisco's hands. "Now get this out of here!" he ordered.

"On it!" Reopening a breach, Cisco quickly leapt through with the kryptonite, vanishing just as Barry grappled back to the ground and landed exactly where the breach closed. In a blink, Clark sped right into Barry's face, grabbing a fistful of his green Kevlar body armor in his hand like it was a cotton t-shirt.

"What do you think you're doing?!" he demanded.

Oliver expected Barry to flinch and stammer in confusion in the face of Superman, and when instead his friend replied with coldness, he couldn't decide if he was impressed or worried. "I ended it," Barry replied in a low voice.

"With kryptonite?" Clark accused. "Where did you even get that? What if you'd missed? You could have hit me. You could have hit Kara!"

"I don't miss," Barry snapped back, not trying to break Clark's grip, likely knowing it was useless, but standing his ground nevertheless. "You did your job. I did mine."

Clark dropped his grip of Barry's front and stepped back, incredulous at Barry's stony answers. Oliver hadn't spent much time with the man, but it had been abundantly clear in Smallville that Clark Kent was a good, decent person. Meaning, he probably wouldn't respond well to "ends justify the means" reasoning.

Letting out an exasperated huff, Clark stared at Barry seemingly for the first time. "You know, Kara's told me about you since you two met. Barry Allen, a hero as kind in his heart as he was good in his deeds. So far, you're not really living up to the description." With narrowed eyes, Clark continued, "This isn't even our Earth. We," he said, gesturing to himself and Kara, "are here helping you, and you pull a stunt like this? What's your goal, to destroy one enemy just so you can make a couple new ones?"

"My goal, my one goal," Barry responded furiously, now getting in Clark's face instead, "is to save my city. My home and my family come first no matter what, do you understand me?" he challenged. "If I have to be someone else, something else, to do that, then so be it." Icy silence stretched between the two heroes.

"Okay," Kara interjected, speeding forward, putting one hand each on Barry's and Clark's shoulders.

"Alright," Oliver said at the same time, speeding in between them as well and taking the opposite shoulders.

"Clark," Kara said, jerking her head to the side, "may I talk to you? Now?" Nostrils flaring, Clark nevertheless stepped away to speak to his cousin, making sure he got in one last glare. Barry didn't back down, maintaining eye contact until Clark turned away.

Moments passed as Oliver watched the cousins have a heated, whispered argument while he gathered his thoughts. "Wow," he finally said to Barry, who apparently had felt no need to break the silence. "That was…I've never seen you like that, Barry."

Barry rolled his eyes. "You know I made the right call Oliver. I didn't have time to make sure everyone was good and ready," he noted sarcastically.

"Right," Oliver said absentmindedly, confusing his brain as he watched, almost in an out-of-body experience, himself and Barry have a somewhat familiar argument from completely opposite positions to which they were normally accustomed. He decided not to dwell too much on it. "But you have to understand his perspective. Kryptonite's their biggest weakness, isn't it?"

"Yeah, and Amazo absorbed that weakness. I took advantage."

"I know," Oliver replied quickly, trying to let Barry understand he was on his side, "but it's a tough decision for everyone to swallow in the heat of the moment."

Barry tossed back his head, his frustration winning out. "Amazo absorbed the powers of the Flash, Supergirl, and Superman. You think I was just going to let that thing roam free in Central City?"

"No, I get it," Oliver reassured him. Holding up his hands in a conciliatory gesture, he continued, "Look, let's just try to move forward with cooler heads. Speaking of which…" he trailed off, turning his head as Kara walked up to the two of them, massaging her head with her hand. Clark kept his distance, arms crossed as a frown creased his forehead and his eyes stared without seeing into the blinking police car lights around them.

"I can't believe I've become the 'mom' friend of this group," Kara muttered. Taking a deep breath, she addressed Barry, pointing a finger at him. "Okay, first off, I'm also not thrilled that you used a kryptonite arrow. And," she continued, rounding on Oliver, "I don't like that you even have kryptonite."

For a brief moment, Barry's façade dropped away as he looked at Oliver curiously. "Oh yeah. How did you get kryptonite, anyway?"

"Later," Oliver muttered gruffly, his own natural personality also surfacing.

"Look," Kara continued, "you don't live on my Earth, and you don't understand the history of kryptonite and how it's been used to hurt me. To hurt Clark. Honestly, I have half a mind to bring in resources from my Earth to take any and all kryptonite away from you. But," she added quickly, as both Oliver's and Barry's body language indicated disagreement with that idea, "I won't, and Clark won't either. I trust you two, and that's enough for him. As long as that stuff doesn't come over to our Earth, we'll be okay."

Barry nodded. "Deal."

"Yep," Oliver agreed.

"Good," Kara smiled. "Now go shake hands," she said, looking at Barry and cocking her head towards Clark.

"What? No!" Barry objected, gesturing with his hand. "He's the one who yelled at me."

"Barry, you don't have superspeed right now," Kara warned, glaring at him. "Don't make me drag you over."

Grimacing to himself, Barry trudged over to where Clark was standing, Kara and Oliver following behind. Holding out his hand grudgingly, he said, "I'm sorry I didn't warn you about the kryptonite."

Clark looked at Barry's outstretched hand for a moment, seeming to debate whether to shake, but his good-hearted nature won out, and he extended his hand to grip Barry's. "I don't agree with your methods," he began, "but it's not like you're the first vigilante I've butted heads with. Although I guess," he corrected himself, looking over in some confusion at Oliver, "you're technically the vigilante."

Oliver held up his hands. "Hey," he replied defensively, pointing at Barry, "he's the one who shot the arrow."

Clark looked back and forth between the two of them, still obviously confused. Kara sighed, turned on her heel, and began walking away. "Let's just get back to S.T.A.R. Labs before my headache gets worse," she said, not bothering to check if they were following her.

…

Author's notes: I didn't like Barry's usage in the episode of "You have failed this city." I felt there were better ways to insert a callback to some of Oliver's classic lines that would actually make sense, so that's what I went for here.

The opening line is directly from The Flash 5x09, "Elseworlds, Part 1."

Rewatching the original scene, I admit the arrow Barry used does bear a similar design to the kryptonite arrow Oliver shot Overgirl with during the Crisis on Earth X crossover, but that strikes me as too important a detail to simply gloss over.