Allowing a game to end Prematurely

[Adam]

As APG pointed out by quoting the actual rule, in your situation, go to the other coach and see if he agrees. If so, shut it down. If not, you've really no choice but to let the winning team finish their passing contest.

If, however, the losing team decides to cancel the game on their own and simply walk away, not much you can do but allow it to happen.

Real world in a rec game with 50 seconds left? I'd pull the plug on the game, too.