This is a combat concept.
Against three or more attackers.
Think of them like bills coming through your door on the same day. You don't rush to pay the one that's the first bill - you rush to pay the red letter, the final demand that threatens to cut you off.
Out of the 3 attackers, one will be the main man, the other will be his 2 mates backing him up.
Take out the main man - the "red letter" with a pre-emptive KO.
Then you can hit the next two with a double tap.
Sometimes it won't work out clean - you get the second man and end up in a grapple with the third, but that's OK, coz you're now one on one.
Sometimes the third man wil back right out of range when the first two go down, which is fine as well - let him run away.