I've realized a helpful tip for finding the cave: the entrance makes a distinct humming noise. You can follow the sound to find the cave. You can also use the sound to find your way out of the cave if you're lost.
Inspired by you I gave this an attempt myself got to assurance and by some crazy odds the moment I get in fire exit a barber spawns literally immediately, Due to my lack of experience with one I grabbed a few things and just left. The barber spawned inside fire exit so I was beyond lucky to have escaped. And then the run ended on offence when I killed a thumper and then another spawned immediately after and started chasing me at mach 5 speed, Blew myself up on a landmine. I don't think it was meant to be
Assurance was having an experimentation by mimicking its older brother Vow, with a mineshaft, Bracken and Maneater spawn, but this only ended up being an Offense.