DISCLAIMER: I own nothing except this idea. Probably. I don't know if I'm the only one who thought of an elevator reveal.
Note: I watched the show in French with English subtitles, so that's why he's "Chat" and not "Cat."
The elevator shuddered to a halt.
"No," Ladybug cried, "no, no, no, no, no!" Her time was running out, and so was that of Chat Noir. "Quick," she said, "face the corner!"
He laughed and did as she said, shrugging. She did the same on the opposite corner of the elevator.
"…You didn't happen to have any food on you?" Chat said, his voice muffled.
Ladybug gasped. "No, shoot!" There wasn't any way to help their kwami recharge, so they'd end up seeing each other eventually.
Chat's time ran out first. He knew she couldn't see, but he blushed a little anyway.
When Ladybug's time ran out moments later, her face went completely red as she pressed her face deeper into her corner.
Chat was the first to speak. "One of us has to use the emergency telephone and call for help," he said. Ladybug was closer, but she'd still have to move to reach it. "And even if we can get help without looking at each other, there's no way we can leave without seeing each other."
Ladybug closed her eyes tightly. She didn't want to admit it, but he was right. After a moment, another idea crossed her mind. "One of us could look," she said quietly. "And that way, one of us could keep their identity a secret. When they open the doors, the first one could walk out with a minute's head-start, and the other can leave when the first one's gone."
"Brilliant, except what would stop the first one from revealing who they are to the second later?" Chat said, smirking.
"Well, if I look—"
Chat cut her off. "No, I want to look. If you're going to look too, that's fine by me, but I definitely want to see you." His face reddened. He didn't mean for it to come out that way.
After trying (and failing) to come up with something else, Ladybug sighed and relented. "Okay," she agreed. "On the count of three, we'll turn around."
"Okay." Chat started the count. "One… Two… Thr—"
He'd turned around as he started to say "three," and was taken aback by the fact that he actually recognized her.
"Chat, are you o—" She looked over her shoulder and froze, her face tomato-red.
"Marinette?"
"…A-Adrien," she stammered, stiffly turning the rest of her body.
"Thank God, it's you!" He scooped her up in a hug, letting out a relieved laugh.
Marinette didn't know how to react. She was surprised that she hadn't turned into a puddle yet, but it was still a possibility. He was hugging her. Adrien Agreste was hugging. Her.
"Marinette?" he said cautiously, pulling away. "Are you alright?"
She managed to nod, not taking her eyes off him.
A slow grin crossed his face. "Cat got your tongue?"
"Oooh, my God…" she said, covering her face with her hands, but she was too slow to hide her grin.
Adrien laughed. "We should probably use the emergency phone now," he said, reaching for the panel of buttons….