Hypothetical: After horn has sounded during a try?

[Shooter14]

Was just thinking about this last night for some reason. What if:

Team A is in the bonus and down 2, A1 heaves a half court shot just before the buzzer. The buzzer sounds, the ball hits the rim, bounces up and B3 and A2 both are going for rebound (let's say the gym is so loud they can't hear the horn). B3 pushes A2 hard enough (trying to keep him from getting a last second tip-in) where you can't ignore it. It's after the buzzer sounds but during the try. What would you do?

I know the ball is still live during a try. But you could not shoot free throws for any other foul that occurred after the buzzer so I was just wondering. Would you just report the foul and game over still?