Do you have literally anything to back that up?
And by that I mean:
cases when everyone or almost everyone on board was killed.
And:
A standing passenger can fall and get seriously injured just from hard braking.
I can point to Muni of the early 2000s. Their then-new trams experienced frequent emergency brake applications in the tunnel because reasons. It got so bad that the braking computer was changed to reduce the rate of deceleration during emergency braking. People were getting hurt, twisted ankles and whatnot. I can't remember anyone dying inside one of the trams. Ever.
The last fatal automobile collision I can think of was idk yesterday? Four dead. Six injured. But that was up in the north bay. The most recent fatal traffic collision I can think of in San Francisco was on the 19th (so about a couple weeks ago).
Here's a non-fatal wreck where the bus was hit hard enough to do a 180. No deaths and six injuries (some of the injured were pedestrians).
https://www.nbcbayarea.com/news/local/6-hurt-after-suv-colli...
One of the first links I turned up was this:
https://injuryfacts.nsc.org/home-and-community/safety-topics...
Deaths per 100 million miles traveled in 2020. Autos: 0.56, Buses: 0.02, Trains: 0.03, and Part 121 air travel: 0.002.
Traveling by bus is dramatically safer than traveling in a car.