Brothel massacre
When Rambo goes to the brothel to save his girl, he starts hitting the guards with a hammer in the head, and even some customers are hit in the balls, even though they aren't a threat to him...
Why the hell did he do that? Imagine being an shy, awkward guy, who is constantly rejected by women and the only option for sex is going to a brothel. And just when you are preparing to have sex, an old crazy dude appears out of nowhere in the room and starts hitting your crotch with a hammer - yikes!