I actually did manage to turn around and tried to get Hamilton, guess what? It was not a plane, the bullets were merely coming from a point. I used x-29 and with careful manoeuvre and speed you can actually turn around in the tunnel sections. You will face another problem though, the shutters get closed once you pass them so you will crash and will not get hamilton because it does not exist. I believe the designers did not think that we would be that crazy to try it out