GTFO: R4A1 - Cytology (Extreme)

The steps to clear this are almost the same as doing the normal version, but at the selection of what bulkhead to open pick Extreme, then head to the bulkhead room and setup - mining and foaming the little door next to the normal bulkhead and the large door as well. Don't worry about the little one next to the extreme bulkhead, just make sure it's closed. The horde seems to love the tight passage on beside that door though, so feel free to mine/c-mine/c-foam that too. There's a lot of gear lying around in this level (not in boxes) so be like Jim and pay attention to shelves and tables.

The bulkhead itself is a class III alarm (2 sets of circles) and inside is your usual bop city. You want to collect two generators and plug both of them into the deepest chamber that features two security doors, but with only a single large roller door leading into the room. Once the generators are in place, seal and cfoam that door. Mine the inside and also put an auto turret (if you brought one) with a firing arc to cover the door once the scum break in.

The trick here is to do BOTH security doors simultaneously. Starting with the team scan on the bottom one, everyone then has to run up to team scan the top door (Jim had to refoam mid way). Once done, Jim was left on door foaming duty while DL and I worked on the cluster alarms for each door (around 16 circles a piece). Easily cleared before the door breaks, and then it's just a matter of surviving.

You'll need to visit each security door so the order doesn't really matter, but you can definitely expect solo scouts lurking within. Stealth hammer is ideal as you will be hurting for supplies. The extreme objective involves typing codes into a terminal (3 codes each), and once you begin you can expect waves of scum to try stop you. It's not so bad though, as long as you can c-foam the door protecting each terminal, and you don't make any typos.

Since you need six HDDs as well for the base mission, remember you can do that at any point after finding the bulkhead key. Just open up the normal bulkhead and do the class II hold (one set of circles). The only challenge here is the door(s) to the bulkhead chamber are probably broken now so enemies can come from three directions (including the now open extreme bulkhead). The solution is simply to fight well, and remember that the autosentry or a mine can give you advanced warning of the direction to overwatch.

Also worth remembering there is another class III alarm blocking the final HDD so make sure you have enough gear to handle that. Once you have all hard disks and are done with both terminals, you've basically won as nothing new will spawn to come and get you. Just head over to the extract spot and GTFO.