[Staten]

I'm familiar with the SR rule :) But, in GURPS damage detoriates so quickly the room would need to be very small for for damage to reflect. A wall 2 meters away from the blast would only reflect 3 points of damage to the point of the blast. Of course, this adds up for more walls.

I reformulated it to the above proposal to keep maths down, and to reflect the fact that where you are standing in the room is not that important..