Phaze, as in Dream Phaze. To dream phaze is to experience an engineered dream. From the novel series Dream Phaze, which was internet forum slang to differentiate an organic dream from an engineered dream.
A warning that dictates that intentionallydoing something agreed to be foolish or stupid will only result in negative consequences for the person doing the idiotic thing.
Jack apparently looked down the barrel of his pistol to see why it wasn't firing. It seems he didn't remember the maxim of "play stupid games, win stupid prizes" and blew his brains out on accident.