Thanks all for responses so far

yeh like there are no antes to steal, whats been happening in the last few orbits, have you opened at all or shoved etc
I would prob just fold and lock it up then keep folding till you get dem AA innit.
Andy,
I think the history is key of some importance here and should effect how we play although having said that I don't think I am folding tens here.
Matt
What we need to know to calculate cEV: 1. How often is the button opening from this position 3 handed? Im guessing its a huge portion of his range.
2. How much of his opening range is he going to call off a shove with. This will be affected by the table dynamic at the time ie how often are you 3bet jamming.
3. Once you have a rough estimate of his widest possible calling off range, what is your equity vs that range.
Only once you have that info can you start forming a conclusion of the optimal cEV play here.
I should've probably included more information in the OP.

The away guy was chip leader when he disappeared, I had 20bb at the time @ 600/1200, villain had me covered. I was expecting the away guy to return, so at that time the villain was raising the button, I was 3b jamming a lot. Think I got it through 3 or 4 times without being called.
Once it became more obvious that the away guy wasn't going to return, and we'd both chipped up from the away guy a bit, there were hardly any big pots. Most pots were won pre-flop with a minraise, a few hands were just being checked down with showdown value, and Ace high or King high won the pot. This was happening more and more as the away guy got shorter.
Can't remember the villain 3betting me at all, might have happened once. He seemed afraid to go out in 3rd. Apart from the 3bet shoving mentioned earlier, I 3bet him a couple of times although nothing went to showdown, he folded pre or folded to my cbet every time. I eventually got caught out, blinds 1k/2k he opens to 4k, I 3bet 10k (Because King blockers are the nuts), away BB obv folds, and he calls. I cbet 10k, he clicks it back, I fold. This knocked me back down to just over 20bb @ 1k/2k, and the spot in the OP happened a couple of orbits later.
Re: #3 in Adiman's post - Tough to assign a calling range. Think he was opening maybe 50% of buttons, and because I should be shoving much tighter when the away guy has 2.5bb and he has me covered, I'm assuming he would call with something like 99+, AJ+, maybe 88/ATs at a push?