Well when I had accidentally drifted on the NTR path with Nicole and I went on a date with her, I saw nothing happening in no subway, all I remember some big guy coming to the restaurant bathroom and he was about to bang Nicole, didn't check the scene further than that, it's a "Hell no!" for me when it comes to Netorare and just load a previous save and correct my mistakes xD But yeah, I never saw any gangbang scene in the subway. If there is one, then my bad, but I don't care either way, I don't play that path, haha.
But yeah, if there indeed is a scene like that, then I'm sorry for false information