Buff up, and be aware you will be moving through no-regen so remove draining buffs accordingly. Do not bring a mount or summon npcs during the mini! It will prevent you from moving forward as it will think you haven't cleared the room.
From The Back Bar 'a bartender with a low-cut top' purchase a pint of Hlegmal special. This will give you a buff called Nature's Call. Essentially this is your time limit to complete the mini area as if this buff runs out, you will be kicked out. The mini area it self is a corridor of 20 no-regen rooms. Each room you advance a mob will appear that you must defeat to move forward. The mob that appears is semi-random and includes:
Every third room from the start, you can REST to have all vitals restored. However this will take 15 minutes off your Natures Call buff so you have to manage this. You can't rest at every stop or you will run out of buff time. After the 20th room, you will reach the end and head into the boss room where it is no longer no-regen. Herbalists can utilize cure light and refresh herbs while in the bathroom queue to stretch out the time between rest stops.
See also