Certain job specific frequencies often go unused

[Kotlol]

You also need to take into consideration how the departements work, in Research and Medical for example, constant radio chatter isn't always necassery, often times your colleague is around the corner unlike for example Security where each officer might be patrolling on seperate parts of the station.

Wow this is a really good way to see it. Medical is generally able to easily communicate what's wrong to eachother due to how much of the equipment is in the medbay. And most of of sci's stuff is hanging around in one spot.

That is "NORMAL" but in reality there are several medical stations on most stations where you can sit too. Aka medical checkpoints, especially in large stations.
This is so not everyone has to run to medbay...
You also forget the often unused job of EMT. Where someone is patrolling the station and responding to medbay calls, picking someone up and saving their lives then port-a-meding them to medbay if it's TRUELY URGENT! But atleast stablizing them on the spot.

While whenever I am doctor there is mostly only 1 or 2 doctors in medbay (including robotcists) if there is 3 or more... have one of you go to another station or roam. You don't need that much in 1 medbay.