Taping the two radios together wouldn't work. These are push-to-talk radios and would have needed someone to alternate pushing the buttons for the conversation to take place.
Neither titanium nor other medical implants are magnetic. However, if Mac's electromagnet were strong enough to pull the gun from her hand, it would have attracted every other loose piece of metal in the hangar to it.
In the scene where Riley & Bozer are in the dark trying to get the satellite link up, and Bozer is shining the flashlight around the area, you can see a crew member in the back come out from behind a plant before Bozer shines the light in the direction of the camera.
Near the end, when everyone is outside the hanger, you can see the shadow of the camera person on several of the crew members one at a time.