I don't think they went all the way since it was all a set-up by that fuck-boy who has obsession with Mieko (the one who get her drunk and took pictures in the earlier chapter). Also, Mieko is an exhibitionist but not a whore. She never allowed anybody to do more than some touching so I think she did K.O. the old geezer as soon as she noticed what's going on.
@HollowCT
So attempted insertion crossed the line but the facial cumshot or attempted rape in earlier chapters didn't? Why are you still here?
I don't know what you expected but *almost* crossing the line is kinda the point of this manga. And sooner or later she will get laid because we all know where this is going (with two rape attempts already).