We alredy had a moment exactly like this earlier in the manga, there was no need for another one... This will just drag it out for another chapter or two before we can resume to make meaningfull progress. Also, cmon Nao, I don't expect you to dodge blows like spiderman, but at least give some back or don't imeadiatly fold next to the dumpster. What's the point of intervening if Sena can't reliably depend on you for a phisical confrontation. She also could have kicked this guy in the nuts when he started to get phisical like the first guy, but it is more understandable for her freze in that sort of situation.