Wino, why go to all the complexity and trouble of creating a binary device, why not pour the contents of a cheap bottle of brandy in the toilets and then throw in a match. I am sure that the resultant fire might need you finding a diversion pretty quick, though there are not many airfields available mid atlantic. Could the answer be that the resultant drop in airside sales of duty free liquor is far more inconvenient to the airport operators than piss*d off passengers are.
There is no such thing as 100% security, a determined attacker will penetrate eventually if they wish. But why go for the cost and risk of such an operation, if the mere suggestion of outlandish plots screws up the travel of a large amount of the population. If the security people were smart, they would focus on the simple and obvious, not invent hollywood style plots.