Iacisrmma & Chabadgal –
1. he was actually referring to a very sharp knife. Yeah, I know I didn’t make that clear – I was trying to make some kind of point.
2. I think the rule that dull knives are more dangerous is only for adults.
3. Why is there a chiyuv to use knives on Shabbos? Can’t you just rip the Challah with your hands (as long as your wife doesn’t object)?