Okay, lets math this one.
A 12'000rpm router with a 2cm sanding drum (TINY!).
The drum has a circumference of just under 6.28cm.
Multiply the circumference by the rpm, divide by sixty.
The edge of the drum will traverse 12.6m in a SECOND. An 8cm drum, just over 50m per second. That's 112mph. 162fps. A .38 Special's bullet probably travels about 500fps.
Imagine bits of your nice normally safe sanding drum flying at your soft compliant damageable body at that speed. Probably very hot and melty by that point too. Unpleasant is too flowery a term for this one.
Russian Roulette is more appropriate I believe. Your fingers won't grow back. Or your teeth, nose, lumps of arm, etc.
DO IT PROPERLY.
Sorry to be so blunt, but that's the way it is.