Expected Value without Expecting Value

I'm currently teaching a class on "Effective Altruism" (vaguely related to this old idea, but based around MacAskill's new book).  One of the most interesting and surprising (to me) results so far is that most students really don't accept the idea of expected value.  The vast majority of students would prefer to save 1000 lives for sure, than to have a 10% chance of saving a million lives.  This, even though the latter choice has 100 times the expected value.