Survivability in side-impacts is critically dependent on side-impact airbags (rib-level and head-level). There is precious little "crush space" in such an impact, compared with a longitudinal collision. Seats are also not normally designed to provide support in a side impact. They actually use a specialized crash test dummy for this test, to measure its effects on the human body.

You can have a car that is very solidly built, like the W126, but this would perform poorly in such a test, because of the impact forces of the passenger with the door of the car, and the lateral whiplash on the passenger's neck.

Side airbags are one of the main reasons we should be considering the newer Benz models.