I am not saying there won't be drag but the reason why you won't see as much air movement inside is because they are in a high pressure relatively static bubble of air.
Most drag that comes off airbrakes is created by the back surface the blade creates turbulent flow and that gets rid of energy. In this case the back of the aircraft retains its shape so not as much drag as you might expect would occur.
this old thing
And this flw is from right to left and you can see the stagnation line in the middle.
If they had baggage bay door and it had popped open I don't think they would have survived to be honest the tunnelling of the cabin of the air would have made changing attitude quite hard.