Running thru the cave to get to the towers. I highly recommend any combination of toughness/blocks/dodging/stealth/superspeed.

Usually, the mesmer does the cave run. I've been in runs where the healer and/or a Scrapper with stealth+superspeed will rush their pals through the cave instead.

I got lucky here, usually the mushrooms are more aggro.

Forsaken Waters (3rd in raid mastery line) is required in order to briefly pause the ticking damage from the fumes.