The ignition system is on when open. That is why it will run when the plug is unhooked from the switch.
Basically when the plug is put into the switch, and there it is in the off position the system is closed and will not run. When you turn the key or unplug the switch you open the system and it runs.
If you tether it it works the same. Tether on opens the switch and it runs. Tether off closes the switch and will not run.
Kill switch is the same. Down is closed, will not run. Up is open and will run. Unplug the kill switch and it is open, will run.
Also if you need it Brown is a ground. and yellow is hot.