There could be an emergency hatch in the roof above the driver (like a school bus, sort of), and/or the side windows.
The rear doors could be closed just after the last person enters, and then the hatch door gets closed/open by a remote release. The struts could slide on tracks on the sides, and let the hatch close, or push it open; not unlike a power sliding door on a van.
Here's two more images; a plan and longitudinal sections:
And I have a new video animation of the CarBEN EV Mk 3.8 model: