Amusing to picture our "3" terrorists carefully assembling 10m drones, each with a 1g shaped charge on it - or does the author think this is something that you can just order from some factory in China, along with the 10 tons of plastic explosive.

It seems to be that anyone sophisticated enough to put 10 tons of plastic explosive in any form wherever they feel like is already quite capable of causing massive casualties.

Somehow, to make this even remotely plausible, we need to intersect a lot of unlikely combinations (a bunch of really bad guys who are hugely resourced, very technical and intelligent, completely uninfiltrated, fighting for some goal that isn't going to be radically harmed by the optics of killing thousands of soft targets).