It sucks to be him but he left the air marshalls no choice. Unfortuantely, the air marshalls couldn't just assume that he was bluffing or that he was mentally handicapped. This reminds me of a case that occured about 8 years ago. A man boarded a bus carrying handicapped children and claimed that he had a bomb. The was was shot a killed, and it was later discovered that he did not have any explosives on him.
You are always going to have stupid people criticizing the police and claiming brutality, but imagine the blame they would throw for the police's failure to act if there really was a bomb involved. It is sad that this man had to die, but in a way, it really shows that there are air marshalls onboard. I hope that curbs some would be terrorists from trying to blow up airplanes. The sad reality is it probably will have no effect since the terrorist would simply blow up the plane rather than making any commotion first.