I had this same experience when a full size pickup piloted by a drunk nailed a utility pole on my rural road at an estimated 45 mph. There DEFINITELY was a feeling of concussion and boom. I thought a bomb had gone off, it was stunning. And yes the engine was a long way down the road from the remains of the chassis.
Yup. Cars are intentionally designed now to come apart to dissipate energy in a crash. Thus 5 grand repair bils for minor impacts. 77 F 250s they arent.
Having recently done a ground up frame off rebuild on one, it is amazing the difference in materials from then to now.. They really don’t build’em like they used to.
Usually, though, the engine keeps going in the direction the vehicle was headed at impact. Accounts at the time reported that the tree was relatively unhurt (usually the bark gets torn off in a violent collision), and that the engine/transmission had traveled at 90 degrees to the direction the car was going.
A few key numbers would help: The mass of the engine/transmission and the amount of momentum needed to launch it the distance traveled (as I recall about 150 feet).
Older Mercedes were tanks, but I'm not familiar with the construction of the newer ones. With crumple zones, etc, (not present when I was a Fireman), the absorption of energy by the deforming bodywork would tend to reduce the stresses on the motor mounts, etc. rather than the more severe stresses of a more rigid coachwork (where the engine would tend to keep moving at its previous velocity while the rest of the vehicle came to an abrupt halt.
With a crumple zone, the deceleration would be less sudden, and the stresses on motor mounts would be less.
Perhaps some FReepers who have better knowledge of the vehicle and its construction can shed some light on that.
If so, it could be determined how far the engine/transmission would likely travel at any given speed--and a minimum of how fast the vehicle would have to be traveling to toss one that far, not counting shearing the mounts.
If the numbers just don't fit, then the ejection of the engine/transmission (as shown by distance of travel) might have had some help beyond the basic physics of a car crash.
The other questionable aspect is the intense fire seen in the videos. When the engine left the vehicle, most of the electrical and fuel system should have been, pardon the expression, FUBAR. Without the primary source of heat or electricity, there should have been no fire. A massive fuel tank structural failure should have spread out more (a couple of gallons of gas can cover an amazing amount of pavement).
Sorry, but I think this needs closer scrutiny.