I was wondering about this just today. How would one transition from a tube full of 00buck to a slug if the situation were to arise? Since its a hypothetical, anything is possible.... Though in a real life-or-death situation with a shotgun, I'm pointing and shooting whatever happens to be in the tube / chamber. Probably not time to switch out ammunition.
Gen4 G22, Mossberg 500, Colt LE6920MP-B