I noticed this when I first watched but thought I was mistaken. Maybe I still am and not sure if it’s even intentional, but look at this face. Doesn’t it look like Matt Smith? I know it’s not this face throughout the rest of the scene, just thist bit. And I’m not saying it’s meant to be the 11th Doctor as part of the story, more of an easter egg. Think about it, this was the moment the 12th Doctor had his big moment. Like Matt Smith stepping through the image of David Tennant in the 11th hour, this is the 12th Doctor ripping off his old face and becoming the Doctor.
"Moffat, you can’t have this couple kiss on tv"
"Kiss? Of course they aren’t kissing. They’re "Sharing oxygen". Kissing indeed"
This was definitely one for the fake fans who complained that Capaldi wasn’t attractive enough to be the Doctor