I haven't seen the episode myself but this may be a spoiler for Doctor Who so I'll just leave the link to the clip
https://www.youtube.com/watch?v=w31UDme_Jq8
No idea if it's for real, or a bait and switch, dream, hallucination, possible future, or just something that will be shrugged off with no trouble.
There doesn't seem to be a "hide spoiler text" option on this forum.