Something bad happened. You can’t remember what caused it, but you know that it caused the Master and Missy to go at each other’s throats.

Now, sitting in the TARDIS, you watch the two of them yell back and forth, seemingly to no end.

Missy crosses her arms and scoffs

“I’m the older out of the two of us, I know better!”

The Master lets out a laugh of disbelief.

“You know better? Like to tell the Doctor all of our plans in a moment of weakness?!”