So the party completed their long rest behind an illusionary wall and when they came out they found an Ettin doing guard duty along with his pet Rust Monster.
The party completely forgot they were wearing the tabards of the previous guards so the Ettin was confused as to why they were attacking. Eventually they got it all sorted out and the Ettin agreed to work for the party for a huge amount of gems. (Party apparently does not know the hiring price of the Ettin.)
The Ettin walked the party down to the next section of cultists pointing out all the places they could have gotten into trouble. They were able to avoid the basilisk lair, the green slime, and the Umber Hulks. The party got a good price though because the Ettin did a good job as a damage sink when the troll guards didn’t get the right answer to the challenge question.
End result was dead guards, dead ettin, and ettin payment back to the party.