Nonsense
Regarding your reference to point number 3:
The intention is that the access to the toilets wasn't restricted immediately after the take off from Jakarta.
This should have been the captains solution assuming that he had no other choice but to proceed with the flight from there, and assuming that the identity of the arsonist was not even suspected at that point.
Instead the toilets weren't monitored or restricted after departing Jakarta and everyone just sat there waiting for this clown to have another go
