Let's write!

 (This was a neat idea! I was going to do a "what if it was 8 in the Lazarus capsule" but this idea came to me while cleaning.  What if our trampoline-like friend Cassandra took over a different companion?)

"There are secrets here." 

Those had been the last words Nyssa had heard from the, well, was she actually a woman?, Cassandra. before her pale associate pulled that lever. The pain was intense- like lightning striking every part of her body. 

"Please!" Nyssa cried, as beams of light slowly trapped her in place,  "What are you doing to me? I can't move! I can't-"

And then the pain stopped.  Nyssa fell to the hospital floor, only to be awoken by the pale man peering at her in shock.

"My mistress?" he asked, confused. 

But Cassandra's awful taunting voice was already swimming in Nyssa's head. She examined herself. "Well, this is new. Hands...fingers...how I missed it! Oh, this is interesting. May not have been a pure human, but there's grace and a regal bearing here. And this mind...this is going to be fun." 

Suddenly there came a buzz and rush of static as the Doctor's voice came over the comm device Nyssa wore. Curiously,  she picked it up.

"Nyssa!" the Doctor called, "Nyssa , where are you? I've found something." 

Nyssa-Cassandra whispered quickly to her associate. " What sort of voice?"

"Language hard to determine, but old Earth RP" he replied, "I believe the word would be posh." 

"Er, hello Doctor" she said into the device. "I'm coming."