I agree that Misery sent him there instead of killing him because she knew he might stop the doctor, She must of had some sort of resisitance to the crown because if Balrog can help move the boulder then she should have some sort of choice over it.
Why would she send him to the Labryinth though and then go wild at him when he tries to destroy the core? Surely she might of known Quote would make it to the core. Plus why would she send Curly to another part of the labyrinth? Or was she sent to the same place but after Quote had opened the door?
I think Misery chooses never to fight Quote and leaves it to Balrog or Omega because she knows Quote has the ability to beat them but has to look like she is atleast attempting to stop him, Thats why at the balcony she is forced to fight you as she is alone on the throne and the doctor is close by watching.
I dont know.. at some points she seems like she wants you killed then the next she doesnt, It's hard to figure out what she truly wants. Although at the end Balrog does state Misery sent him to the Sealed Chamber to rescue the two of you.
I think Misery didn't know which option or side she truly wanted to take until the Curse was broken and she saw how far you would go to save your friends, I think she had a heart felt moment when you backed away from the core to protect Sue and realized which side she should pick.