Did the officers beat him until his face looked like the picture posted above? Did they kill him?
No we did not, but he had some bruising on his arms and legs where we were trained to strike to stun the large muscle groups. We were able to hold his head stationary so he could not bite us, but he definitely wanted to.
Sometimes a resistor will overcome their pain threshhold and then there is precious little you can do other than use weight to hold their limbs down until they run out of steam. Some PCP abusers do this as well.
The teen I fought with went positively primal, drooling, animal noises, scratching, and trying to get up the whole time. Humans can be immensenly strong when stimulated in the right or wrong way...