Student or Learner
Is this sentence correct?
She said that she could not remember seeing Dr. Liang and Dr. Yoon and where she saw them.
If she doesn't remember seeing them, then of course she doesn't remember where she saw them. The last part of the sentence doesn't make sense to include.
However, you should link the phrases with "nor" instead of "or."
She doesn't remember when she last saw Dr. Liang, nor where she saw him.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.