Chapter 33:

I'd come up, before, with the hypothesis that HPMoR Voldemort was actually Necessarily Evil after the fashion of Eliezer's proposed supervillain gambit, but I dismissed it by assuming that Voldemort had crossed the Moral Event Horizon already. This chapter, though, makes it very plausible again via an explicit motivation (and a Shout Out to Foundation, as well). On the other hand, Quirrell could just be playing one level above that explanation.

One thing, though: is it public knowledge that Lucius Malfoy had been a Death Eater? Because it seemed to be a very dangerous thing to say out loud (not that Quirrell need fear Lucius, but that it seems foolhardy to so easily signal that he need not fear him).