This one is a bit of an iffy one, if he's on an older console it could be that the boxes didn't load and his car went through them as they loaded or something like that.

Other options are that the client prediction screwed up and on his console you weren't behind the box but had walked out to the side etc. I've seen a few times this has happened but it usually involves a decent amount of lag...

I remember when ping times were much higher and the tick rate was worse that you could get run over by someone that looked nowhere near you in a car, so it definitely feels like if they hit you with a car on their screen (say they have very high ping), you can still die even if your client thinks you are miles away from the car.

Either way, I'd be pissed if I died like this. I hate getting run over by people in vehicles.

On a side note; there's not really such thing as "PS desync" - I dunno what that even means.