Ejection seats throw you straight up through the cockpit, then forward and away as far as those little propellant things can push. No, they're not "guided" at all. If the plane were upside down, the seats would have rocketed into the ground. You get shot forward in anticipation of the tail of the plane coming up on you quickly as if the plane were moving quickly. In the vid, it's almost an illusion that the seats guide the pilots 🙂 Ever seen ejection vids? The pilots don't go up through the cockpit and straight back as the plane rockets forward... they seem to shoot straight up.
nik