He erupted rom the pudding plant. Is there more to it? If something happened before what's currently on the screen, it had nothing to do with it. It's a shooter game. There is no progressing storyline.
PS: Dan Paladin, I don't care if you don't like them, make better cut scenes. If you're going to have any cut scenes, you might as well make them good. I deserve some visual pleasure whilst my thumbs cool off. Otherwise, what's the payoff? Yeah, it's fun, but it's still something to work for. They're like enjoyable benchmarks for your effort.