@Froschkönig The simplest way is to use a true emergency stop switch and wire the PSU positive through it - that's what do. So when I hit the button, it kills all power to the printer until I reset the switch.
I connected only 2 of the 3 wires and it seems to work fine. I'm not sure about the accuracy of the sensors, they seem to be a little bit off but thats fine for me.