i don't have a source but there's something about their mouth or teeth that make it very hard for them to suffocate prey the way a lion or hyena would. They kill their prey through shock and blood loss from disembowelment which means basically eating it alive like you said.

Oof, I'm glad I didn't witness that (not that the zoo would feed live animals to them). It certainly would've changed my opinion on them, even though it's just their nature.