There seems to be a place you can get to where you can observe the operating room, or another doorway that is guarded - this time the guard, masked and breathing in rasping gasps through the mask, seems to be asleep in his chair. The gun held loosely in his hands.
What do you do?
Try to slip the gun from the guard's hands.
Sneak past the sleeping guard into the next room.
Move to observe the operating theatre.
Sod this - head back to your room before the other guards come back.