If you were Alonzo...
and knew that you were going to be killed within 24 hours by the Russian mob if you didn't pay them a million dollars, and had a feasible but very illegal way of obtaining a million dollars. Would you really roll the dice and decide to take on a new guy you knew nothing about the day you're planning on pulling all this off and involve him in it?
I love the movie and think Washington and Hawke were brilliant, and I realize the viewer is seeing the movie from Hawke's perspective so we don't know any better, but after all the dust is settled and you start to think about things after the fact, well...