Find your access key to log in. ? xp
You need Marcus in your squad. See the Military Base location.
Trick the security guard
After killing the two guards at the elevator entrance, go downstairs using the Vault 14 key (if Marcus is in your party, he'll say he's reminiscing about his youth). A super mutant guard will be waiting around the corner and will ask for the password. The password is "Slavic Wardrobe" (check your conversation level; if your level is low, the correct option won't be available). If you attack or give the wrong password, all mutants on the level will attack.
Free the slaves.
- Free Sirian on level 2. 500xp
— Free Murdoc at level 2. 500xp
Kill all mutants and monsters on the level and talk to the prisoners.
Alternative: Tell the guard (if you entered the safehouse peacefully) that you've been ordered to take the prisoners outside and shoot them (speech check?) and talk to each prisoner. XP is the same (500+500).
- Free Chris the slave at level 1. 500xp
You need to destroy all the monsters and mutants on the level and talk to Chris in the kitchen.
Kill Ardenius. 900xp
Descend the stairs to level 4. After a short conversation, Ardenius will attack you. Be careful, he's well-armed and has 615 HP.
Ask Dr. Dawson to make special SM armor.
Three sets of metal armor and one set of supertools are required to craft the special armor for Marcus. The doctor's lab can be reached by going through Ardenius, but this doesn't affect the ability to craft the armor.
When talking to Dr. Dawson, ask him about Wanamingo and take it with you as a pet.
Shelter 23
DO NOT BRING YOUR CAR HERE
Find the entrance to the shelter.
Get the access key from the man in the shack dressed in robes.
Turn on the elevator power supply.
Turn on the light generator.
Kill all mutated rats and the rat boss. 10000xp
Hunting rats have 120 HP, 200 XP
Source: falloutmods.fandom.com.