New options:
Agents can lock doors when they have the key to its lock
Guards can break locked doors when chasing a specific interest or when they're stuck
Guards use the keys they have on them to both unlock and lock doors while walking through them. Additionally, guards keep a memory of the keys they had in their inventory. When they lose a key, they will not notice until they try to open a door locked with that key and it fails. Enforcers have keys to security doors, no matter their inventory
Reworked guard elevators: Guard elevator doors must be locked and unlocked by guards for them to pass through. If an agent manages to interrupt a guard between unlocking and locking the door, they can use the elevator as an alternative exit
New augment that allows the user to access VIP exits and lvl2 security doors

Changes:
Maintenance Corridors do not automatically unlock at alarm level 5 anymore and can be repeatedly locked and unlocked at their control unit at will. Enforcers have keys to them.
Many modded interactions with lvl1 security doors also work for lvl2 security doors now
The "Janitor Clearance" augment from Age Of Lever gives access to Maintenance Corridors
Other small stuff

Added failsafe for realistic layout code that prevents an infinite level generation loop that could apparently happen in rare cases
Fixed single teleporter prefabs using slightly wrong coordinates for their placement evaluation

New special prefab (in the former "special rooms" pool): Experimental Teleporters: One-tile teleporter pair that the agency can use once per mission.

Expanded OMNI Mainframe level generation tweaks option with tweaks to other story missions (mid 1 and 2)
Added option to make Maintenance Corridors appear more or less often (adjusting its requirement)

Increased difficulty requirement for lvl2 guards in the strongroom, the power station and the lvl2 checkpoint from 6 to 7
Set a maximum of 2 Maintenance Corridors per level (was infinite before)
Fixed hunting guards trying (and failing) to enter the VIP exit

New option to fix OMNI Mainframe objective room placement (general improvement; vanilla code tried to be consistent in its placement but wasn't)
Elite and Lvl 2 Checkpoint spawns a little bit less cover

Split Facility light rework:
Using a teleporter now draws attention of other guards in the elevator to the end point. If there are none, the closest guard to either teleporter will investigate.
If the player uses the teleporter while under Overwatch, the aiming guard will get an interest at the end point (similar to moving behind cover).
Guards turn to their next path step while teleporting instead of keeping their facing from before the teleport (easier to predict and dodge for the player).
Guards require and use 1 MP to teleport instead of it being essentially free (mostly a bug fix, free movement can cause some weird behavior; teleporting is still free for the player).

New Layout: Realistic

Fixed non-agent player units not being able to use the teleporter in the split facility

Fixed silly mistake that could potentially cause facilities with the wide layout to change on loading a save (not the kind of Facility Flux I'm going for here)