And the day is saved thanks to Karane! Though if either of the two of them called out for Rentarou, he would have woke up, tore through the tiled floor, and piledrive suplexed the three guys harassing them. Shizuka was saved because a little known fact about Rentarou is, he can hear the very atoms of his girlfriends as they move about. His senses are so fine tuned for his girlfriends, he can hear through solid titanium should they whisper his name.
He has yet to show his true power, but soon you will come to understand that there is no being more powerful in all of existence, then Rentarou when it involves his girlfriends. He is at 100% all the time, but his power level doesn’t have a set limit, you need only watch as he overcomes all barriers, and becomes a god (monster) of love. He can weaken himself at will should his girlfriends need him to, and he can maximum overcharge his power on a dime should his girlfriends require it.
The question is not “if” Rentarou can do something, it’s just “when” will he? You need only give him a reason.