OK, let's try that out then: NTensity will block both door (as in the picture 5 posts up) but pass the connecting wall 1 line behind the X instead of 3, so whoever comes into the room will be in their own little 'back room' (AND have to break through *another* 10' section to get to the front).
He was also at 1/2 HP, so no, not 18. More like 4, I think.
However, I forgot about hardness, so he may have survived. Um.
In that case, could I revise my action?
I could use Craft Action to move instead of my Haste, then I'd have two attacks at the barricade. It'd mean I couldn't try to Hide there, but that's a small price to pay for leaving an enemy alive right next to me.