Your .first. task should be to get a knife if you do not start with one. Why would you go anywhere without one? As for realism, I can’t say that I’ve ever actually tried to tear a pillow apart, but I’m reasonably certain that it isn’t really all that easy to tear rags of random articles of clothing. If they’re already frayed or well-worn, sure, but that’s a special case.
Kinda bugs me that the tailoring kit has 1 cutting quality, but it can’t be activated to cut things up.