Do you want to wear an on-body camera while on duty?
Over the years, I've heard multiple accounts of handcuffed subjects who later escaped or attempted to escape. One particular incident involved a young kid who fled on foot. His ability to outrun two officers with his hands behind his back demonstrated just how focused a person can be if he wants to escape.
Trading blood with suspects is not a good idea - even if you do knock them out with your punch. Instead, learn four strikes that can lessen the likelihood of injury and transfer of blood.