It's absolutely unrelated matters. There always was a possibility for one pilot to barricade in the cabin. And in any case, he could just bash his co-pilot with

It's absolutely unrelated matters. There always was a possibility for one pilot to barricade in the cabin. And in any case, he could just bash his co-pilot with something and do whatever he wants. If you got pilot who wants to crash the plane on board, you already screwed up, good thing it's very rare occasion.