So, I just discovered an infinite XP glitch with the deathtrap by accident. Maybe infinite is too strong, but I haven't gotten to an end yet.
I killed The Warrior, and had just deployed the deathtrap when he died. Then, as all the volcanic rakk are flying around, deathtrap was killing them. Along with the skill that gives deathtrap extended life with a kill, he just keeps killing them, and they keep respawning.
Been doing it for some time, and deathtrap is still going strong! Gonna stop in a minute to avoid over-leveling, but pretty slick!
"If you can't make them see the light, make them feel the heat." -Ronald Reagan