If both pilots became disabled, and unable to respond to calls from the cabin crew, would the cabin crew have any means to open the inviolate cockpit door?
Reason I ask is perhaps one pilot disabled the other to carry out some plot, but before that pilot either died or became unconscious, he retaliated in some fashion to disable the other pilot.
Now in this scenario, we have two disabled or dead pilots behind a locked cockpit door, the plane on autopilot until it flames out 8 hours later.