The concubines lost the emperor's face before everyone by tripping up as they were being handed over to ML. This meant that they couldn't go to the emperor with any grievances because they had disgraced him.
Later, most of them understood reality that the ML was never going to favour them and chose to ask the MC to arrange for them to be married outside. One of the concubines schemed along with another concubine, the wet nurse's girl and her maid to try and drug the MC. She got caught before she could succeed and was punished. The other concubine who had egged her on was stubborn that she wanted to "serve" the ML. So the MC sent her to live alone locked up in an isolated courtyard where she couldn't leave till the ML called for her.