Elisabeth Sladen and Brian Miller (who were married from 1968 until Sladen’s death in 2011) both appeared in Classic Who and New Who: she as Sarah Jane Smith, he as Dugdale in Snakedance, a Dalek voice in Resurrection of the Daleks and Remembrance of the Daleks, and a tramp in Deep Breath.

Though their time on Who did not overlap, they appeared opposite each other in the Sarah Jane Adventures episode The Mad Woman in the Attic:

I actually didn’t mind Death in Heaven that much but one thing I hated was this

I really didn’t care that she was throwing the keys away. I wasn’t afraid for the Doctor because of this

Moffat himself wrote out the need for a key to open the TARDIS. It even works for Clara, which Moffat also wrote

So this all seemed like an empty threat. Sure you can explain it away by saying something like the doors have to be unlocked for the snapping to work in the first place but that’s never explained. I assume the snapping works at any time. I might be nit picking but I don’t care. It was annoying and ruined the emotional impact of the scene for me.