I was surprised to see that passengers just remain onboard their cars, considering all the safety restrictions applicable for operation in the Eurotunnel.
There are other "Auto trains" like this in Europe as well - I mean trains that act kind of like car ferries to get around an obstacle (instead of the Amtrak Auto Train or many other trains in Europe that mainly serve the purpose to cross larger distances and avoid driving for a whole day).
One example is the Sylt Shuttle in Northeastern Germany. The island of Sylt can only be accessed by train or ferry (through Denmark). Besides regional and InterCity trains, Deutsche Bahn is also operating car shuttle trains. It seems the official web site is only in German:
Startseite but if you search online for the Sylt Shuttle you will find pictures.
Another example is the "Autoschleuse Tauernbahn" in Austria to cross a mountain connecting the ends of two valleys that are not connected through a road (there are of course alternative, longer routes you can drive to avoid the train, especially if you travel longer distances). It is also one of Austria's main train lines which connects Salzburg and Villach in the South. An official flyer with a map can be found on ÖBB's web site:
https://www.oebb.at/dam/jcr:7d6bdb0...91e5ef/folder_oebb-autoschleuse-tauern_en.pdf Nowadays you have to sit in the passenger coach while travelling through the tunnel, but in the past you were allowed to just remain in your car.
I'm sure there are others than the two examples I mentioned.