MacBooks used to have a key combination (left cmd shift option and power) that could be used to kill power instantly. In the schematics, these keyboard keys wer

MacBooks used to have a key combination (left cmd shift option and power) that could be used to kill power instantly. In the schematics, these keyboard keys were hard wired to the SMC microcontroller's reset line, which would remove all voltage to the motherboard upon reset. With the T2, this still exists, but you need to wait more seconds and use a 2step combination. This is a pain because you can no longer use it to do an emergency shutdown.