It's natural instinct and Donnie's not sure he'll ever grow out of it, that urge to make himself scarce the moment some unexpected people show up, doubly so when they're humans. He may not be terribly impressed with these guys either, but he still preferred to avoid trouble.

It becomes clear this is not Accelerator's line of thinking. Donnie resists the urge to face-palm at the blunt response from the esper. Not that these thugs help the situation.

"Seriously, what is it with you people always instantly categorizing us as aliens??" he sighs, exasperated. "I'm not even in costume!" What now? But Jupiter Jim doesn't exist in this Earth iteration, so the reference would have been lost either way.

Accelerator's prompt gets him a flat look as Donnie turns his head towards him. "You're kidding me." This is exactly the opposite of avoiding trouble!