Re: Surviving Vulcan Elders.
Spock also knows of the universe being overwritten by changes to the past (City on the Edge of Forever and probably First Contact.) You would think that if he wanted to minimize his contamination of this new timeline he'd be working to get back to his own. It's not like taking care of 10,000 Vulcans is that big a job. It's a good sized town worth of people, not even a city. Even if there aren't other Vulcan colony worlds (and it doesn't appear that there are otherwise why not settle the survivors on one of them rather than finding a new wold for them to live on) the Federation could probably have a colony up and running in a matter of months if not weeks. All he's doing by sticking around is making himself a target and putting those around him in danger.
We can admit that we're killers ... but we're not going to kill today. That's all it takes! Knowing that we're not going to kill - today! - Kirk - A Taste of Armageddon