Hello and welcome!
The ooze is no joke and can be deadly, but it is a suggested twist and the party can avoid it in a number of ways. Ambushes and special abilities limit the conflicts the party can engage in, but they are rare.
By design, some encounters in the dungeon are just too much to handle and failure leads to compromise. If the players embrace this, they will think twice before just walking right into a trap or waltz into an ambush or start drinking water from a scary crypt.
Sounds like you had a great session.
I wouldn’t say you are incapable of playing by the rules. Everyone had a good first session and is starting to grasp the game.
The game rewards creativity and risk, and Afraid is an appropriate consequence for that bold move to grab the bone.
A lot of new players don’t like the idea of going back to town during the middle of the adventure, but it is there for a reason, and it is better to head back to lick your wounds than die unceremoniously in a dark crypt.
Please let us know how the next session goes.
Grind on!