Averaging utility works only when law of large numbers starts to play a role. It's a good general policy, as stuff subject to it happens all the time, enough to give sensible results over the human/civilization lifespan. So, if Eliezer's experiment is a singular event and similar events don't happen frequently enough, answer is 3^^^3 specks. Otherwise, torture (as in this case, similar frequent enough choices would lead to a tempest of specks in anyone's eye which is about 3^^^3 times worse then 50 years of torture, for each and every one of them).