So what happens when a rat trips the rat line and baby raper's computer goes up for no reason?
A-you don't bait the trap...duhh...
B-then we don't have to deal with baby raper anymore!
the heat Thermite putts off can't be contained by a "crucible" so you would have to use another explosive...preferably one that is self-oxidizing. self oxidizing compounds tend to be fairly volatile, thermite isn't because of its extremely high activation temp.
I don't have this problem, but if I did I would keep said computer in my basement/dungeon, dig a 3 foot hole, run the wire up out of the hole, put the drive in a bag of thermite with an ignitor, and bury it. if it goes off, it won't trash my entire house.