I got this achievement while working on some of the other ones after creating a boost session on here. There was a group of five of us that worked on Fallen Idols and Supreme Survivors. During one of our sessions, we divided the teams in two, one with 3 other with 2 people on each side using the Train Wreck map. The team going for this achievement and Skill... or Luck? one stood put while the other 3 ran over to their side. Tap "B" and then press and hold "Y" to do a melee kill. Once the person is killed and respawned, they rushed the other side again. Took only 2 gamer sessions to get this for everyone.