Every vehicle I’ve had with an electric parking brake operated the same way. Hold the park button while moving and it starts clamping the parking brake down, let off the button and it starts to release. So you can basically PWM the parking brake in an emergency.

Unfortunately it only had older still photos and videos, nothing from the last dive. Looks like they had the camera configured to send the data to the onboard computers and those were smashed into a soild mass, of which, no data was able to be recovered from.