I'm surprised at all the people saying it's a difficult decision...
EASY CALL. Doesn't mean you have to feel 100% confident, or happy to get your chips in the middle, but there is really no other reasonable option besides calling. Out of every hand that it would make sense for him to do this with (TT, JJ, QQ, KK, AA, AK) you crush ALL of them except one.
you can't live in fear of the chip leader, or you'll never, ever become the chip leader.
There is a great chance they both hold an A....there is a great chance you are facing one pair and one Ax hand.
you never "get it in bad' with KK preflop.....you just get coolered.
In this case, he got coolered.
When you factor in the pot
odds from the other short stack it's such an easy call.