How did Two Horns survive the explosion in his HQ?

By sheer badassness. Seriously, with all the plot holes and improbably survival distances from huge impacts and explosions throughout the movie, this is where it stops for you?

I don't know, but it was a straight up rip-off of Breaking Bad. https://www.youtube.com/watch?v=O47UY80VKfo&hd=1

Two Horns and his office is just like Tuco's, and both scenes involve negotiation, ending with an explosion.

And don't waste time reading this line, it's just my pointless signature.