((It probably would go through the walls, but I'm not sure the blast would necessarily be all that powerful beyond the room. Especially when you consider that the room might get a bit close to 0 K in a few moments. And that the room is very well-secured.))
((If you freeze the bomb you will disable it. However freezing the room wouldn't do much because:
Energy in a kiloton: 4.184*10
12 Joules (hey, using superscript for what it was intended!)
Energy required to raise the temperature of a kilogram of water by 1
oC: 4.186*10
3 Joules
Energy required to raise the temperature of a kilogram of water from 0
oK to 373
oK (boiling point): 1.561*10
6 Joules
Assuming that the gasses that condense after freezing the room behave like a ton of water and are capable of absorbing every Joule of energy possible until they boil that still leaves you with (4.184*10
12)/8-1.561*10
6*10
3=5.214*10
11 Joules of energy, equivalent to 124.6 tons of TNT. And an eighth of a kiloton is 125 tons of TNT.
And that is without taking into account the radiation and the shrapnel (but maybe it's not a nuke but some kind of high tech explosive so those things may not concern us).
So in short, if you don't freeze the bomb,
this happens.))
((EDIT:Fixed a small math error.
And for comparison: The bomb in the
Oklahoma bombing was equivalent to just 2 tons of TNT.
This
cold war weapon could obliterate bridges and power plants with the equivalent about 10-20 tons of TNT.
And explosions are magnified in enclosed spaces.
So if my character had any knowledge of physics, he would be shouting for everyone disable that detonator whatever it takes or start running, because if it is indeed a 1/8 kiloton charge they would only be safe near the elevator or maybe not even there.))