Minato's sword is a holy grail beam saber, that I specified can cut whatever Minato wants it to, so I should hope it does a little more than base sword damage.
Space time dorm is called that because it is technically in eight places at once; But for practical purposes the dorm is in none of the places unless someone opens the front door at which point it's position becomes fixed in one of the places for a short time.
I have mentioned this before too.
To put it simply if someone who is not allowed tries to enter the dorm, it would almost definitely fix itself somewhere else. This is not infallible, someone with time space abilities could get around it, and someone with high enough luck could just walk right in thanks to simply turning the odds in their favor. Probability manipulation would also work.
Flying in through a window with no luck stat, no time space skill, no probability alteration, and no talking to me beforehand definitely does not work.
Though I am having trouble not laughing at the concept of a persona protag not being able to kill a shadow. Probably a different sort of shadow but the thought is still hilarious.