AVClub: Early in “Cold Fire,” Tobias shows up at the commune to send Martin on an assignment back home. But before he gets to the details, Martin points a finger like it’s the end of a murder mystery. “You killed her. I know it was you, Tischbier!” Yes, we all do. He handed Martin a shovel and told him to bury the body. This isn’t something Martin would be just pretty sure of. He would know. He would know Tobias knows he knows. The blame would be a given. For a drama that runs on secrets, it’s important to keep track of the things the audience knows already and can go unspoken.