That makes a lot of sense. Probably hospital/facility security and the intake or admin personnel’s systems.

Most contemporary CCTV systems are IP based. Not surprisingly, network security prevents a lot of cross network traffic (or even network interconnectivity) between different system openers. The cost of allowing those connections is far more than just putting in your own system. I have a significant airport client that has 6 cameras on one door going to a generator control room of a parking garage with some antennas on the top level. Between the airport authority, county (they own the airport), power company, cellular antenna provider, and a few Federal agencies, the real estate for cameras on that one door is quite limited.

I hope the hospital visit is a helpful one for whomever.