A few things to consider:
-BMW is RWD and does not have the transmission in the engine compartment nor does it have the half shafts to drive the wheels and the added mass in those areas. With that said- BMW does an amazing job engineering safety to counter that- MB not so much.
-The wheel getting stuck there is what caused the intrusion- I'd bet if you repeated the test the wheel may end up somewhere else and there would be no intrusion.
-This test is a WORSE case scenario- there is NO brake application meaning that there is no front end squat or dive. The brake dive would take weight from the rear (BMW's are close to 50/50) and move it off the rear axel lightening it and helping the rear come around relieving some of the blow.
-BMW tests in real world scenarios to make their cars some of the safest on the road- a few months ago we saw what happens to an M5 at nearly 185 mph involved in a crash- the occupants survived. There is a facility similar to Volvos that tests what would happen in the real world and they design to that rather than any "test". The Lincoln is an example of being designed to a test- that is a car you would not want to be in in such a crash ever.