Bodhi knew that one way or another, this was the ex-Presidents' last robbery. The FBI was on to them. In order to maintain their surfing lifestyle, they needed to make a big haul. Bodhi is also reinforcing that the rules are what he says they are, as this exchange just before the robbery points out.
Utah: Bodhi, this is your f__ing wake-up call man. I am an F, B, I,
Bohdi: Yeah, I know man. Ain't it wild? That's what makes it so
interesting. You can do what you want, and make up your own rules. Why
be a servant to the law, when you can be its master?