At the end of the third one did the bird deliberately pick the wrong mug so the evil dude would die?
Nah, I got the impression she thought it might have been the right one, but was eager to let him try it first to make sure
She new
I sort of had the idea she was warming to indie so decided to point him (him beind the bad guy) to the wrong cup, she didnt know which cup was right but knew that the Shiny gemed cup was wrong :P
In that sort of situation there is only one right cup so the probability is he would get the wrong one. He should have forced her to drink from it first and that would have removed one possibility.
Really though it was predictable that they wouldnt have had a huge gold goblet covered in gems.