Visible crew/equipment: While Rob, Mel, and Harry are standing beside the table, Harry blows out his deathday candle to celebrate his 5 years being underground, and in the wide shot, their tape marks, including a red T-mark, are visible on the floor. (00:05:55)
Visible crew/equipment: When Jane straight up tells John Swift that she's taking a "vacation" so she'll be out of his hair, just as Jane walks out of her own office, the red T-mark is visible on the floor at the doorway. (00:15:45)
Visible crew/equipment: When Lexy is scared in the classroom and stands up, there's a closeup of her eyes, and you can see a very clear reflection of a lighting bounce-card in her eyes.
The Man with the Umbrella - S1-E3
Visible crew/equipment: When the second game starts and everyone is climbing up the stairs, two of the players are talking. The camera is in front of them going up the stairs. At one point you can see the shadow of the camera on the wall to the left.
Visible crew/equipment: After Raines shares details with Kellett about Semien's crew, when it cuts to Semien waking everyone up, just as he announces his contact with Belgian Federal Police, there's a visible T-mark taped to the floor behind Andre's cot. (00:24:25)