I've read both autopsy reports on Paul Walker and the driver Roger Rodas. There was soot found in Paul Walker's airway, therefore he was still breathing and did burn alive. As for Roger Rodas, there was no soot found in his airway, which means he died of his multiple injuries due to impact. The first link is for Paul Walker's autopsy report: http://www.autopsyfiles.org/reports/Celebs/walker, paul_report.pdf and this second link is for Roger Rodas's autopsy report: http://www.autopsyfiles.org/reports/Other/rodas, roger_report.pdf