I agree that Harry's actions weren't even close to optimal in that situation, but you have to cut him some slack; after all, he just found out that he was a fork of Lord Voldemort, that his best friend had been killed by his trusted mentor, and, oh, let's not forget that that mentor also happens to be Lord Voldemort. He'd have been hard-pressed to be thinking completely clearly after a series of revelations like that. (Mind you, all of these revelations sans the last one came from Quirrell himself, who's hardly the most trustworthy character out there, but the shock and emotional impact is real nonetheless.)