Visible crew/equipment: On the runway, two shots after Castor Troy says, "This is a big gun. Fly the f*ing plane," there is a side shot of the Hummer. As the camera pans in closer, the reflection of a crew member on the filming vehicle, which moves beside the Hummer, becomes visible at the Hummer's back end, just before it cuts away. (00:10:25)
Visible crew/equipment: In the shoot 'em up scene at the hangar near the beginning of the film, right after Tito and Wanda take down Pollux, when Troy shoots an agent in the stomach and the agent flies back - you can see at least two cable wires pulling him backwards. You can first notice the 2 wires when the agent is running in slow motion right before he shoots him. (00:14:15)
Visible crew/equipment: After Castor is captured at the airport hangar, when Sean pulls into his driveway the crew is reflected on the vehicle's surface. (00:18:15)
Visible crew/equipment: When Sean first visits the Walsh Institute, he, Dr. Miller and Dr. Walsh walk in front of the circular glass window to view the ear reconstruction. In the next shot facing them, the reflection of a boom operator holding the boom pole is visible on the glass in front of Dr. Miller and Sean. (00:24:50)
Visible crew/equipment: When Sean sees himself for the first time as Castor Troy, he takes the coat rack and slams it into the tri-fold mirror. The right side mirror is knocked back, and both the cameraman and camera are briefly visible in the reflection. (00:37:05)
Visible crew/equipment: When Buzz and Wanda stand in the outer room, in the first shot, the camera pans around and faces the agents' TV, showing the video feed of Pollux in the interrogation room singing about his tiramisu. On the agents' TV screen, the reflection of the crew's rather large black square screen is visible (on a stand) in front of the windows (to block window light and view of the crew/equipment) and just as the camera faces the TV head-on, a crouching crew member begins to stand (seen at the left side of their TV screen). (00:59:05)
Visible crew/equipment: During the prison escape when Sean Archer (as Castor Troy) is running up the stairs towards an exit, a crew member's foot and lower pant leg can be seen in the upper right hand side. (01:12:25)
Visible crew/equipment: During the raid at Dietrich's, when Sean (as Castor Troy) hangs on to the chain then grabs hold of Pollux, in the close-up Pollux's safety wire is visible in front of him. (This is not Sean's safety wire, as seen in the following shots.) (01:39:05)
Visible crew/equipment: When Sean (as Castor Troy) is doing the 'water skiing' thing, trying to hang on to the speedboat's chain, in the close-up the harness he wears is visible under his wet white shirt. (02:06:50)
Visible crew/equipment: When Sean (as Castor Troy) shoots Castor (as Sean Archer) with the speargun, when the spear is finally unloaded, in the side shot there is a thin guide wire pulling the spear tip towards Castor (as Sean). (02:09:25)
Visible crew/equipment: At the L.A. Convention Center, just before Castor Troy (as Sean Archer) disarms the bomb, there are a few shots of all the extras evacuating the area. In the interior shot, that looks out through the glass doors onto the street, the tracking crane arm with a seated camera operator and camera on its platform is visible as it shoots an exterior crane shot of all the extras, which was seen among the previous shots.
Visible crew/equipment: At the Walsh Institute, after Sean gives his ring to Tito, when the stainless steel sliding door closes, the camera and a crew member, or likely the director, looking behind the camera lens is seen in the glass window reflection.
Visible crew/equipment: When the red boat has hit the barrier and Castor Troy and Archer fly through the air, you can see a wire attached to the front of the boat just for a split second, then when it falls in the water and explodes.
Visible crew/equipment: When Cage throws Pollux through the ceiling window, the support wire is seen in front of Cage as he's hanging from the edge.
Visible crew/equipment: When Pollux falls through the glass roof, you can see his harness pulling him back.
Chosen answer: Although they were on the same side, Troy is currently posing as Archer, which means he would have to do everything that the FBI would expect Archer to be doing. The whole point of the raid was to take out Archer, as well as Troy's gang. He would have rather risked killing part of his own gang than risk exposing his identity to anyone else.
Casual Person
That doesn't really make sense. In the scene, he goes out of his way to shoot him and smiles while doing so, carefully and slowly. Was not a collateral damage situation. The question is why he deliberately goes out of his way to kill him.