My son is a SS agent and I can assure you that NO ONE is more distressed over this than the agent driving that vehicle. And we need to wait and get the determination from the scene reconstruction as to who was at fault. These guys are given EXTENSIVE driving training and I'm sure are exceptionally cautious and careful drivers because they often have the president, vice-president or other VIP's as their "cargo".
If the agent was at fault, he will and should be treated the same as any other driver responsible for a vehicular death.