Gas lines, brake lines, are often under hundreds of psi. The radiator is filled with pressurized, scaling, hot liquids. Even my speedometer/console is filled with argon gas. And, what of air bags?
So in addition to the O2 I carry in my car, just in case this happens, I've now realised I'll need to wear a football helmet and protective gear.
This is vital, important because... I mean.. well because...
(The above is what explaining IT security is like, to a normal person)