When Rogan dies and MacGyver goes to Roxy apartment, the microphone is visible (just a second) at the mirror in the wall.

when MacGyver and roxy are talking in front of her trailer after she pulls up in the porshe, even though this supposedly is taking place in Chicago you can tell this was shot at the BRIDGE studios in Vancover where Macgyvers sound stage work was done and whose exterior and parking lot doubled in several episodes for the Pheonix Foundation Western Division. The bright Orange gerters spanning the two buidlings is a dead giveaway. In Fact the trailers that are supposed to be Roxys star trailer and equipment trailer look pretty close to RDA and Dana Elcars trailers from an Entertainment tonight episode, so maybe they just used what they had on hand

when macgyver goes to carlas house the first time he comes in a sliding glass door that has nothing on it. when mac turns and says hes going to come back in again there is a full peice of paper taped to the glass window right below macgyvers right shoulder. when the scene moves away from the door the paper is gone again.

At the end when Carla is holding the gun, pressumably about to kill herself, we catch her reflection in the mirror. Its obvious the gun is pointed over he shoulder, at MacGyver, and not at her head.

When Mac and Roxy (or was it Carla?) are climbing the elevator shaft Carla says all the doors were bolted shut except for the Penthouse. This to Mac's disbelief. But um, why is that actually? To make sure the elevator attempt would work in case they got into the shaft? Or is it because it's a private elevator for the penthouse only?

Because it's a private elevator which only goes to the top floor. No need for those other doors to work. They're probably only there as emergency access doors and can be unlocked from the outside by emergency services.

As MacGyver pokes his head up out of the top of the elevator there is a visible jump in the picture indicating a cut in the scene.