Similar experience here on the ~first day. I managed to crawl thru to the font seat to exit.
I kinda figured it was the child safety latch, but when I inspected it "appeared" to be disengaged. I thought I might have have my first serve call.
Turned out the switch was not fully "clicked" into the open position. I inserted a house key into the slot and forced the the switch to the final OPEN, clicked position. Done!
Kinda funny in hindsight to be trapped in the back seat of my own car!