Over and over and over again, the champion spawns, is called, and is killed by those camping it before ANYONE ELSE ON THE MAP can even get to the spot.
Consequence? If you want to even have a chance, you have to pick one of the spots where a champion you need spawns, and camp it. If it doesn't spawn, oh well, better luck next time. This means you spend the majority of your time camping, in between camping for the next meta event.
Sorry, but I don't find this non-game sort of "game" to be very much fun.
Given the nature of this community these days (and I fear my respect for it has deteriorated severely in the last couple of days), this was IMO easily predicted. Unfortunately, this means this achievement was designed to be this way. Very disappointing. Leaves me rather apathetic about the game as a whole.