These shredding teeth are brutal.  The 10" wheel turns against a six inch thick anvil, giving it a force great enough to shred more than just paper.  They eat metal on a daily basis, and have even munched through a bowling ball or two.  If you look close you can see how the metal teeth are welded onto the solid cylinder.  The cylinder torque is so great that the welded teeth will break off before the cylinder will stop turning.  Even then it would continue turning at full speed until an emergency stop was initiated.  The bottom line?  Don't get in the way of that shredder because it won't stop for anything.