9-435: Pristine, Downport Administration
I think Oliver would know, given his skill set, that the Communications Bureau, subject to the dictates of the Vizierate, is responsible for much of the maintenance, operation and support of the Dominion’s non-military communications network. This includes the Message Packets and the ground and space-based communications arrays for communicating with them. In short, a Comms Bureau tech wandering around a Downport in heavy protective gear of some sort is not something that would draw much attention.
So he might be on a message ship?
Or he could’ve easily snuck somewhere else?