Turn one wall-smack, and driver was seriously burned. The other person in the photo is chief Brabham mechanic Denny (or Dennie) Moore.
Looking for other photos to do with this.
https://www.oldracingcars.com/brabham/bt12/A week later, on 1 October, while testing at Indianapolis, the Brabham was badly damaged after McElreath spun at Turn 1 and hit the wall. The car burst into flames and McElreath was seriously burned.
Car was also involved in several other accidents, including the tragedy at the 1964 Indy 500.