Ayo

Something similar happened to me too.

I was testing out a new Nodegraph i made for the map since the current one isnt all that good.

To test it i spawned NPC rebel's in parts of the map, tested if they used the nodegraph correctly, despawned them and repeat.
When i spawned them in the small 2 office boxes with the ticket booth windows in them, something weird happened.
I use the Holographic Hud thing which has the radar and on the radar a dot suddenly showed up, i didnt spawn it it just was there- and moving.
On the recording i could see that it was a Civilian npc holding a camera. It followed me but before it reached me i noclipped out of bounds. After that it was gone. I tried to replicate this but i cant get any results.

Try spawning multiple nextbots, then watch the nextbots where they will go. This way you could find him, or maybe kill him.

seems liek this map is intentionally scary, the creator just seems to be very vague about it.