Gotta say, I hate the trend where the protagonist shows up to stop an ero scene anytime it doesn't involve him. Like I know most people aren't into the non-con thing, I get it, it makes most people uncomfortable.
So if you're not going to follow through on a scene like this, don't start a scene like this. Don't start a scene with content that's going to make people uncomfortable just by its inclusion just so you can have the protagonist win some white knight points by swooping in to save the day.
Now you've made most of the audience uncomfortable and disappointed the people who are into those kinds of scenes. This is a lose-lose situation for everybody but otaku who use the protagonist for projection.
I don't read ecchi manga to see this four-eyed, shaggy-haired dipshit show off how much of a Nice Guy he is, I read ecchi manga for ecchi scenes.