This is one of my favourite fics of yours really, I don't think Arthur is being OC, he's fragile maybe he is not like tony, who tends to show more his feelings but I imagine a reaction like that for his part; he runs away for the fear of being in love... Yeah I'm sure Arthur would act like that!
I hope you can write another one-shot or longfic, you've the best english I've read!

I won't cry, I won't cry, I won't cry...I hate you (but I love you) TT