Trauma doesn't work like that though. It's not a game of top trumps. An event becomes a trauma event when a person experiences what they perceive as a threat to life and their brain fails to store it as a regular memory, so it keeps on popping up as a real-time event when it shouldn't. It's kind of a mechanical failure, a processing glitch.
What counts as a trauma event doesn't depend on how objectively "bad" the original event was but on the brain's failure to process and the resulting negative experiences and behaviours.
Eg you get folks who have lived through wars and not developed PTSD, but years later they're walking down the street and are first witness to a nasty car accident. They can't get it out of their mind, find themselves on high alert on that particular street, then they start avoiding that street, then they start feeling on edge when they're on their alternative route - could be the alternative street has similar trees, or someone walks past them who looks like a passer-by on the original street, whatever - their stress levels go up, so they avoid that street too, and the next near alternative, and so on, until the area of potential threat has considerably widened as their personal world shrinks. Maybe they ruminate obsessively about road safety, pedestrian safety, seek out stories of road disasters to prove to themselves that the measures they're taking are necessary. Or alternatively perhaps it is just too stressful for them to even think about road accidents, so they avoid talking about driving, then avoid driving, then avoid talking to their friends in case their friends talk about driving ...
That event, although not the worst thing that's happened in their life, and despite them being entirely uninjured, has become a trauma event. Not because of the event itself, but because of how their brain has handled it.