As Enzo lies in the backseat of Denny's car on the way to the vet that night, it occurs to him that Ayrton Senna didn't have to die; he could've walked away. He tells the reader that the day before the fateful race in Imola, Italy, one of Senna's friends was seriously injured on the track and another driver died during a practice session. Senna, upset about the safety conditions on the track, assembled a new driver's safety group on the morning of the race. However, despite thinking seriously of retiring and not participating in the race, Senna decided to race.
Compare the lead-up to Senna's death to the events that took place before Enzo was hit by the car. Both of them experienced low moods, and their ensuing freak incidents or accidents (snow in Seattle; the other drivers getting injured and dying) seem to indicate that bad things are about to happen—if one follow's Enzo's belief in manifesting.
In the extremely dangerous Tamburello corner, Senna's car left the track at 190mph and he was killed instantly when suspension pierced his helmet. Or, Enzo suggests, he died in the helicopter en route to the hospital, or he died on the track. Enzo says that there's still great controversy over Senna's death, as on-board footage of the race disappeared and politics entered. In Italy, if a driver dies on the track, the race is stopped, severely affecting revenue. However, if a driver dies in a helicopter, the race can continue. Enzo wonders what the truth is regarding Senna's untimely death at the age of 34, and answers himself. He says that Senna, a great man, died because his body had served its purpose, and his soul had learned whatever it came to learn and was free.
Take note again of Enzo's mentioning of how money influenced the reporting of Senna's death, and remember that Enzo sees money as an entirely negative thing. However, despite the intrigue and mystery, Enzo is able to make sense of Senna's tragically early death by choosing to believe that Senna's soul had learned everything it needed to. This provides Enzo with a way to make sense of death in his own life and further shape his sense of destiny.
Enzo thinks of this on the trip to the vet, and tells the reader that if he'd already accomplished what he was meant to, the car would've killed him. But since he wasn't killed, he knows he still has work to do.
Enzo is able to use Senna's death to make sense of the fact that he didn't die. He escapes this incident with a renewed sense of purpose.