Hers Truly attempts to avoid bedtime by claiming potty. So, I let her. Then she won't sit on the potty. So, then it's bed time, which only gets calls for potty. This goes on until she sits on the potty, because sitting on the potty is less bad than going to bed.
Once on the potty, I read to her. Every time she stood up, I closed the book and announced "diaper time." This went on for quite a while, through many repetitions.
Eventually, it really was bedtime.
This is slow going. We will eventually get over this emotional block.