Rysith

I noticed while trying to organize my troops after expanding in July (building a second base, hiring new troops, transferring half of the initial squad to the new base so it wasn't staffed entirely with rookies) that the soldiers (from my initial starting squad) that I had transferred to the new base appeared in the troop lists in both bases and, while they could only be in one Chinook at a time could be assigned to the Chinook in either base. That doesn't seem like desired behavior...

I think I've had this happen to me as well, though it was with a rocket launcher (through an already-broken window). While killing oneself with the rocket launcher seems a bit more believable than the machine gun, it killed only the square the soldier was on - no smoke/flames/destroyed other tiles/etc. that I would expect if they had actually missed by enough to hit the wall rather than the window.