I don't remember much from the movie.
But its some kind of war movie.
A guy goes to some place (school or something) where its just boys, they learns up to be soldiers or something.

In one scene they have to swim under the ice from one hole, to another. And one guy who is there ( who I think was bullied and small) swims half then stops swimming. The other guys can see him drowning under the ice but can't help him. Or something.

That's all I remember. Please help!