I have spent one full night (about 5 hours) sitting in the torture chamber (as the camp seems to be as well)
1. attempting to get the goblin torturer to spawn (seemed to be every 5 spawns or so, sometimes more)
2. trying to get the box.
I don't expect to see one everytime I kill him but for a "common" drop according to the wiki (which I understand could be wrong), it does seem to be a bit much for what it is.
I'm curious if the box is dropping at all? if it is dropping, should it be listed more rare than "common"? I have seen 3 eyepatches and no boxes which leads me to believe it is either broken or it is misrepresented in the wiki and needs to be updated.
http://wiki.project1999.com/Inferno_Goblin_Torturer