This brings up an interesting point, our view of morality is heavily skewed. If you made me choose between something bad happening to my partner or 10 random people, I would save my partner every time and I expect every normal person in the world to choose the same.
Also, where did the human come from? Are they already on their deathbed, prolonged in this thought experiment for only a few fleeting moments? Were they themselves a murderer?
Collectively we kill and eat around a billion rabbits a year, around 8 million in the US. They aren't kittens, but they do have a similar level of fluffy cuteness.
It's not quite "one million to one"; the meat from 1 million rabbits meets the caloric needs of around 2750 people for 1 year.
If they were spawned into existence for this thought experiment, then the human, probably.
But if even one of those kittens were mine, entire cities could be leveled before I let anyone hurt my kitten.