(is going to be reading a lot on the degradation of PETN to make a well informed explosives expert post)
Hahha...I was even thinking to myself, set it off from the helicopter with a radio remote detonation and blow that fucker up. Might be epic to watch, though cord would be difficult to use in a situation like that. You can still go ahead with using a shitload of detcord and something to blow it up, getting to the building across the road then leveling it would be a possibility.