I've never gotten the achievement for being "self-sufficient in the investigation" despite always doing all of the investigation stages myself. As in, not sending Jocasta to the officers deck and instead going yourself, not sending Jocasta to the plasma drive chamber and instead going yourself, etc. You always have an option to skip the investigation stages and have other people do them. But I never did, and I don't have the achievement.

So now I realize that it probably means these flavor choices too where you let someone else speak or do something. It probably means you can't even do those either. So you can't let Pasqal get you access to the cogitator on the officer's deck, you can't let Heinrix interrogate the fake cultist, you can't let Jocasta interrogate this guy, etc. Which is unfortunate, since these people all add to the scenes.
The things we do for achievements....