You'll want to complete the Introducing: NuCaloric contract as soon as you can in Marathon. This faction is all about consumables and has some very worthwhile upgrades that'll get you free Patch Kits and Shield Rechargers daily—and not those crap ones either, but the actual bonafide products that'll heal you up fully.
During this quest you'll have to find a way inside a Tick-infested building on the Perimeter map and retrieve the NuCal Employee ID from inside. Here's how to do both.
How to to acquire the NuCal Employee ID from the infested building
First off, you'll want to head to the Perimeter map—remember to take plenty of ammo. You'll have to kill a fair few Ticks and destroy some nests during this mission, but also, since there's only one location where you complete this important early contract, you'll likely bump into other players, even in solo.
Once you arrive on the map, head for the Columns area in the south, between the South Relay and Overflow. Thankfully, there's only a single building in this area—a one-story structure with a 02 on the outside, a scrawled orange Tick symbol, plus a load of brown gunk and three Tick nests.
You need to enter this building, but when you try the door, you'll see that it doesn't work. Instead, you'll need to climb the ladder outside and use your knife to smash the vent cover on the roof, letting you drop into a storeroom. Looking through the window, you'll see that the inside is filled with Ticks and nests, too.
When you're ready, you'll want to open the door and blast the two nests in the next room. If you run out of ammo, remember that your knife will also work. After that's cleared, you'll find another door on the right side and another room with a Tick nest inside. In this room, you'll find the NuCal Employee ID on a shelf to your left. Pick it up and then interact with the terminal in the same room to complete the quest.
Now you can leave, though watch out for other players as you do, as they might have been hanging around waiting for you to complete the quest.
