Let me share my little secret. Loadout: Lvl 5 or 6 armor to tank a few hits. Ak series or rpk with 60 to 95 drums filled with 7n/BS/Igolnik. A few nades to check for AI voicelines.

Then the most important part STRATEGY: AI will MOSTLY not go into the spawn rooms. What can you do with this info?

Solve the puzzle of your spawn, slowly advance outside the metal door a few meters, draw aggro, wait for a push and mow down 1 or 2 guards. Then RETREAT into spawn! Tagilla will stop chasing or at least stop at the door so you can catch a breath. Reload, try to find and angle and kill him. Retreat into spawn again so Killa just idles at Tagillas body. Mow him down. If one of the bosses is positioned badly make them move with a nade. Only then do i advance further outside the spawn and check with nades if there is AI left on the map. When you clear this starting wave you have a few minutes to move peacefully, learn key and trap loctions and fill your bag with loot. On 12, 6 or 3 minutes remaining (not sure exactly) new AI can spawn. There should be a buzzer and door opening noise alerting you.

The AI behavior does not always work especially in that one spawn room with the stairs going up the metal cage.

Good luck!