In the previous episode of Dept. Q, we saw that there could be a couple of motives for Merritt's disappearance including her mother's fortune and/or her cooperating with reporter Sam Haig regarding the Crown Office.
It feels like the department continues to get further away instead of closer to the truth, which is kind of frustrating six episodes in if I'm being honest. The mystery continues to build in Dept. Q episode 6 on Netflix. Here's a recap of what happened. Spoilers below.

Carl Morck is being threatened
Carl gets a call from Fergus, the inspector who was looking into Merritt's disappearance when it first happened four years ago. He has a bad bruise around his eye, and he delivers a message from those who came to him, asking Morck to stop asking questions. The obvious first suspect here is Graham Finch.
One of these goons also threatens Jasper, who was waiting for his stepfather at an ice cream shop so they could talk things out. When Carl follows him out and beats him, he gets blood spat in his face. And oh my goodness. The amount of rage and then the blood on his face were giving Matthew Clairmont vibes from A Discovery of Witches. Tone it down Morck.
The Dept. Q team finds out that Stephen Burns' daughter was driven off the road from another car while the Finch trial was going on. And so, this leads to the belief that he was threatened and perhaps that's where the "corruption" in the Crown Office came from and why he asked Merritt not to use Kirsty as a witness. His daughter was threatened, and he did what he did to protect her. At least, that's what we think right now. We'll see if that's really true.

Merritt might be able to escape in Dept. Q
Elsewhere in the episode, the investigation into Carl and Hardy's incident continues agonizingly slowly and apparently the only person who knows what they're talking about is Carl himself. I mean, seriously? The detectives on the case don't know anything unless Carl tells them. Sigh. They have a number of potential suspects and Carl goes to see them all lined up, but none of those men is the shooter.
Merritt didn't appear in this episode very much, but the ending is intriguing. As she's being given food per usual, she notices that the airlock on the hatch is broken. Then she hears the woman yelling at the man she's working with that she told him multiple times to fix it. Hmm. Merritt, and us as viewers, are seeing this may be an opportunity for her to finally escape. Will it happen? We'll see in the next episode!
Be sure to check out all of our episodic recaps of the series, here. Dept. Q is now streaming on Netflix.