Question: What exactly happened to the first pilot? Who killed him?
Corrected entry: The bomb was described as having a pressure trigger, so they couldn't drop it out of the window. Later on, a gunshot pierces a window, and all the windows blow out. Either the bomb should've gone off, or they could've dumped it.
Correction: The person closest to the bomb expected to die, and they were fighting with guns and hand-to-hand, so getting to the bomb, unpacking it from all the luggage, and finding a place to throw it out of the plane was not a reasonable option.
But because of the broken windows pressure in the cabin changed, they were above 20000 feet. So the bomb should have exploded as it was pressure-sensitive. But it didn't. Not to mention that the passengers should have died at that point because of immediate pressure change.
Answer: He was poisoned.
Who fired the dart from the lavatory to the pilot?