In my opinion, I think the stalker signal is some sort of nanobot drone made by the Arirals to spy on Dr.Kel. And that the live video feed of the signal is actually the video transmission from the drone to show what the drone is seeing to the Arirals.
No joke, this event happened immediately after the event where the Pyramid Tripod came to the base to suck up all of the light orbs, so when I got the signal preview of the top view of the base, I had thought it was initially from the Tripod's point of view and thought nothing of it; then the following signal's image was through the vent of the signal processing room''s ceiling and all the hairs stood up on my body. The way this game consistently knows when to pull the rug out from under you when you get too cozy is so incredible.
I’m at around day 40 in my first/current playthrough and this is the closest I’ve come to actually not playing the game again due to how scared I was lol. I don’t do well with horror games and have only been able to keep playing this game simply because of how much I love its concept, this shit rocked me to my core
When this happened to me I switched the song to Evangelian's tumbling down and opened the locker when it peaked. Gotta say, was scared, but upon opening the locker I was met was laughter, because DrNose just force crashes the game like you weren't expected to actually open it. Upon resuming, you spawn next to the locker, and I met a 2nd crash when I started the next signal with the locker open. Crazy times.