Maybe not his actual head detached from his body so fast, but all of the information it may have contained about other terrorists lurking out there in the shadows. Then off with his head. Henry VII used to do that, interrogate his enemies and wives before their heads were severed. That led to even more dangerous heads (dangerous to Henry at least) rolling off the stage.
Opportunity lost. But it did exact revenge. Thing is, we could have had both, identification and perhaps locations of other killers and his damn head.