Thou shalt not let thy mind wander whilst straight razor shaving!

I think of SRS as a PID loop (Proportional, Integral, Differential). This is basically a control system that seeks to keep a process stable. Think of it like you are sitting on a hill in your car and you want to apply just enough accelerator to stay on the incline without rolling back or going up the hill - you are static.

When you have all of your SRS process perfect, the perfect shave results, which also means no blood! But this is very intentional, and your brain is the computer controlling the entire system. If you dump the program or do anything to jump out of the control loop - yikes!

This explains how even the most experienced SRSer can still get nicks, cuts etc.