I read that, too. They couldn't roll it over by conventional test methods due to incredibly low COG (battery under carriage), which also improves handling, i.e., safety. The lack of large engine allows for improved safety in many ways not least of which: large front crumple zone. Elon called the lack of engine "unfair" in regards to comparing safety to ICE cars. The crush machine broke after applying more pressure to the roof than had ever been applied to any car's roof before. Have I mentioned 0-60 < 4s?