The one way to GUARANTEE your survival in the 'shroom kingdom' is the use of the biohazard suit, only thing that'll ever harm you while wearing it are the "chompers" that well 'chomp' with their nasty 'gawp'.
Yes it'll be slow and 'cumbersome' but you will be immune to all attacks and hazards except the bites of the chompers.
As of the fluids yes there is one in the burrower nest outside of the south-western elevator, but there's also a canister of the fluid in the storage room in the Tchortist outpost which you'll gain access to once you've 'scouted' the faceless outpost out.
Hint: DO NOT talk to the Tchortists in the DP before you have been 'mind probed' by the faceless.
Also want to say that all the "shafts" supposedly for the gate mechanism don't matter at all except the one you DO need which can be found next to the obelisks in the "labyrinth".