I've always thought the transporter set up on DS9 was a bit weird. Is there another transporter, except the cargo bay transporters, apart from the one in ops? Why did the Cardassians set it up like that?
It was only a mining station but they were very concerned about security as you can see from the episode Civil Defence, so why have a direct way to access ops like you said?
In the same episode Dukat beams direct to ops and then tries to get out the same way. He fails and is also trapped so they're probably not meant as an escape route.
Maybe it's the way Cardassian ops is set up and they're all military, so everyone there is armed and combat trained and they feel secure. It might also be the most secure place Bajorans don't have access to on the station, making it hard for them to use in an escape or an attempt to take over the station.