I've had this happen several times to me. It's a "feature" when you exit your vehicle next to an elevator, you float off into the blue abyss. Obviously the situation at hand is this exact "feature" because ye exited the galaxy into the upstream of the Bio Lab elevator.
Yep, second time I've seen this, happens when you exit a vehicle onto a grav lift as mentioned above. The grav lift becomes endless.
Nice. The only downside was it kinda wrecked the attack just a little when half of the platoon's MAXes flew off into orbit, but I can live with that, for the sake of 2001 references.