Because of the movement involved, Clem's grenade will not be thrown until the end of round two, O'Connor's movement for the round will only carry him up to the door, but no further than that, so I am seeing them either on both sides of the doorway or stacked up on one side.
Snow, can go ahead and shoot the rivets on one side of the hatch.
Sammy can throw a fireball in there, but if she can't see a target, it won't affect anyone except the Heavies.
If O'Connor's doing something important let me know, otherwise we are waiting for Snow as the last action of the round.