I found a much better way to get this achievement, a quad kill including yourself, and multikill with a projectile through a vent. (maybe more)
Game Mode: Hillcampers
Score to win: 200
set the lobby to an 8 player lobby, and fill it with bots on easy.
then just charge the chefolet all the way and fire it into the hill. After doing this for a few minutes, I got all 3 of those achievements.