고 끄다

…and then switch it off

"-고" chains an action or a quoted line to 끄다 "turn off". Most of these lines are about a viewer bailing out: they'll go "this is boring" and just switch off, he said "see you next time" and turned the TV off, you have to switch off right after the intro. It also covers the polite send-off — say goodnight and then turn it off — and putting out a fire: why are they telling prisoners to put out the wildfire? Its opposite is 켜다 "turn on".