To Vasdamas,
Follow the red line(s) on this pictorial walkthrough.
As soon as you spawn, grab your weapon(s) of choice by pressing "E" or enter to spawn it and get it. Then run for the hills! Shoot your way towards the house.
Watch out for crawlers when you get in house. Crawlers and Flesh Pounds. Blast them away, then head up the stairs to the last room on left.
Grab the door key by the wall on the foot of the bed.
Head directly downstairs to the jail gate to open it. But beware, gorefasts and bloats will spawn to greet you hello. Then they will slap you silly!
After the aftermath of zombies slappings, you take your ARS to the backyard, over the turnstile(s), and into the lowering/raising platform to lower you to the catacombs.