At current, what I'm seeing is that PETN has a relatively high flammable explosion point. So it can be burned easily enough without setting off an explosion. But if subjected to a rapid and powerful detonation shock it will go off quite easily. In fact a way to get rid of PETN and a few other plastic explosives is to put small amounts no more then 3 Kgs or so in the middle of a fire pit, cover it in wood shavings and douse the shavings with diesel fuel and set that alight. If there is a great deal of PETN needed to be get rid of, then several fires set apart from each other at the same time can be used.

There is still a chance (slim mind) of the burn causing a detonation. But the small amount of the recommended explosive shouldn't cause a huge problem. 

Mind you the way the RP situation looks they aren't going to be able to burn all that separately. My vote? A few incendiary grenades, then run and hope it doesn't take the building down.

Yes I looked it up.

Yes I'm hyped...

Yes I'm hoping it all explodes. ;3