When in doubt, go with Moffat's cracks, hahaha. I like that idea though, that's super interesting! They're both far from who they were when they were traveling together. ;______________;
So many choices! If she's there in the TARDIS right when he walks back in from peacing out from Clara and throwing A+ shade at Eleven in the process, he'd be right back in Waters of Mars headspace and confused as ever to see her face. I'm not sure what conclusions he would draw, but I am digging the concept already! Do you want me to start something like that, and I can leave a plot post for us to tag on for ideas in progression as we go--or do you prefer docs?