under 2 min to go, team winning is told to keep it in, team winning loses ball out of box and a player from losing team has clear shot at the g.b. he scoops it gets possession for 1 sec. and ball is checked out of his stick. does team losing still get ball

it's hard to imagine a "clear shot at the ground ball then having possession for a second before stick is checked."
Sounds like the posse was right on his tail. Best in that situation to kill the play once the ball comes out of the goal area and give it to the losing team. Think of it in these terms: the worst that should happen to the losing team is that they get a whistle and then a re-start with everyone five yards away. The best would be a clean break-away leading to a fast break. Your scenario above doesn't sound very "clean" so best to kill it immediately and award the ball.

The losing team should still recieve the ball. Sometimes in the heat of the game players will continue to play, like in basketball when a foul is called but the player with the ball still shoots it after the whistle. It is a diffrent sport but the same type of idea.