Board Thread:New on Red vs. Blue Wiki/@comment-26814288-20140714172808/@comment-30133540-20140714200040

Sadly, people do think this. Let me shoot it down.

They have different voice actresses, Sister is clearly too dimwitted to be a doctor, and the doctor's name was revealed to be Emily Grey. Meaning, there's no chance they're the same. Washington only recognized her for the most practical reason ever that everyone overlooks even though she explicitly stated it: she performed surgery on him and her voice at the beginning proves this.

I don't understand where the idea that she was Sister came from, but there's the reasons why she isn't.