On one level you can understand why glasses-chan had to be rejected: you can't have two perverted spa scenes back to back. That'd be repetitive.
Now, to remain in line with realistic character behavior up to this point, you could have a scene happen offscreen. But the readers would be angry at the author. In a way it's almost brilliant - this way, reader anger is directed at the character and not the writer.
Myself, I'd still have gone with a three page montage going over Perverts In A Public Bathroom #2. I know she's just a third wheel, but glasses-chan deserved better!
(Housewife-chan doesn't even work. And she gets it all. How unfair is that?)