While writing my newest piece of fiction I ran head first into a massive bought of writers block. Quite simply I have my main character encounter a brutal fight involving a close friend, he picks up a pool cue and sets about turning the attacker into hamburger meat. The thing is, this character is a shy, quiet guy, he avoids conflict throughout the entire story, even going so far as to allow his house to be ransacked rather than put up a fight. So my problem is that the story hinges on his violent outburst but I don't feel that it's realistic for the character to walk into the bar, see his friend being pulverized, pick up a pool cue and wade into battle like a Norse berserker. I'm wondering if anyone could provide some advice on how to make this scene more realistic?