The steel passenger safety cell has specially constructed roof pillars, integrated roll-bars, cross-struts in the instrument panel and behind the rear seat and strong longitudal struts.
The hood will fold on impact, leaving the windshield intact.
Rigid Drive shaft tunnel and instrument panel prevent the engine and the gearbox from penetrating the interior.
A collapsable telescope steering wheel column is placed outside crush zone.
A theoretical design is nothing worth unless proven under real circumstances. BMW put a lot of time and effort crush testing the 6 series coupe.