Pagers don't use normal telecom systems, and they're not limited to paramilitary organizations. They're very useful in any critical application because they have low infrastructure requirements.

The comment you're replying to explains how they're used routinely in most hospitals in the world for this purpose.

You can't buy pagers off stores on the corner, either. They don't have SIM cards and most of them can't report back to the network, so they need to be pre-configured by the network operator. Just the same way, if you work at a hospital and are issued a pager, it will be issued to you by your employer and you won't be able to pick it up off the street.

In a country with extremely unreliable telecom infrastructure, it's not at all unlikely for an organization to use pagers, especially if it operates emergency services, and they would have to be procured through that organization.