The post by "Voldemort" was an obvious joke/fakepost, though, and Eliezer's comment was on the mark even if he did use a webcomic to illustrate his point...
What makes you so certain that the Voldemort post was a joke, and not simply a sociopath posting on an alternate account to avoid the social consequences of holding such a stance? Certainly, there seem to be quite a few other people here who would pick immortality over saving 28 other lives, if you put the two choices "side by side".
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: