Yeah, sorry about that. I was just observing the body cams work the other way. They record audio in advance of being activated for video recording. Some bad cops made some incriminating statements right before they activated the cameras and got caught by that feature.
That depends on the camera. I have never worked anyplace with bodycams where they had a pre-recording loop. Many (but not all) of the current models do so, but, budgets being what they are, not every agency has been able to transition away from the older ones just yet - and some agencies do not have them at all.