alums Janelle Pierzina and Rachel Reilly face a new set of trust issues on Monday night's episode of, and ET has an exclusive sneak peek! When the contestants' group fails to complete their scavenger hunt-like challenge, Pierzina suggests that Reilly may be the «snake» contributing to their downfall. follows a group of strangers dropped into the wild and left to figure out who in their party is the saboteur designated to undermine them. «There was a couple moments where I was getting really frustrated with Rachel,» Pierzina says during the group's debrief.