Thermite is some nasty stuff. Back in the day (Navy, 70s-early 80s) we always had a flat-pack of Thermite in any safe that contained classified material. In the event of potential attack or overrun one would pull the igniter cord on the pack and it would destroy everything in the safe in about 10 seconds. Depending on the container, it would also destroy the safe... Nasty stuff.
My first reaction was utter horror, but it’s not as ghastly as it looks. See:
https://freerepublic.com/focus/chat/4262383/posts?page=20#20
Now, when it dumps it all at once in bomb fashion, it’s intensified of course, and when it lands on a combustible structure, does quite a number on it.