Oh, there is a threesome planned in that location!
I just kept the main threesomes in the school lockers, because I want the player to be able to do the girls' stories in any order, or even go monogamous if they want. So locking the threesomes behind Lily and Amy's scenes would be a no no :)
But other threesomes in other locations are planned! They're probably gonna be a little bit shorter than the current ones, but they're gonna happen!