So from watching a walkthrough by the developers waaaaaaay back when I knew I could fly hover drones into certain vents. Well I just completed a late game optional mission that I know I had watched the devs play back before the game released and I realized for the first time... that the game never game me an option to move my drones into these vents. Am I missing something? Did I encounter a glitch? Is there some sort of not - so - obvious action that must be assigned to my drone to get it to go into the openings to the other side? Do let me know, as I thought I was missing something before, but now after doing this mission I am positive my drones aren't going through the "slots" in the environment that they should be able to enter.

Thanks!

Your drones can only enter a ventilation duct when combat mode is active.

This sounds exactly right - next time I see an open vent I'll give it a shot while in rounds but I'm sure this will take care of my issues, thanks!

Is there a way to "force" combat mode when no enemies are around? Or is it strickly when I encounter an enemy?

Some user-generated modules allow you to toggle combat mode on or off (generally by clicking on your own character), but the official campaigns don't have this feature, so you can only make use of the ventilation ducts while in the middle of an encounter with enemies.