I'm no expert. It would seem to me, though, that cutting a string on an undrawn bow would be considerably less stressful than dryfiring a bow primarily because the bow is undrawn. There's a lot more energy stored in the bow when its drawn. I'm not saying that cutting the string like that is a good idea or that it would not cause a problem, just that it's probably not as stressful as a dry fire. Good luck.