Well, that stinks! I'm not sure how'd you do it in this scenario, but I know explosives need to be in a "confined" spot to do much destruction, otherwise the explosion just dissipates without much more than a bunch of noise. Like when they use dynamite to break rock it gets placed fairly tightly into a small hole and I believe the hole is packed shut over top of it...that's the part I don't know how you'd pull off with tannerite.
Yep, this is exactly what happened. You have no way to confining the Tannerite so it just chooses the path of least resistance. Oh well, live and learn.