Her expression seems to be saying something like, "oh, it's you guys. ...Mikuru, I stopped dating those guys because they were boring; are they going to be less boring?"
To which Evil Mikuru would obviously reply something like, "Of course not! That's the point! It wouldn't be much of a revenge if you *enjoyed* this!"
And then the guys try to turn on Evil Mikuru and she beams out. Haruhi is then bored to tears despite their rape, and Mikuru's revenge is achieved.
Alternatively, Haruhi discovers that being tied up makes things more interesting, and becomes interested in BDSM. Revenge failed. Then post #872243