Stupidity: At the beginning, young Indy knocks out the driver of the car, pulls him out, and just leaves him on the ground by the car while entering the car. Neither the knockout nor the unconscious driver lying around are noticed by any Germans in the vicinity. Not even by the soldier who opens the car door and the officer who gets into the car, both of whom immediately appear after Indy has gotten into the car. (00:06:00)
Stupidity: Despite being wanted by the law, quite possibly the most wanted man in the US for multiple murders, disrupting the most historic parade of the century, and with CIA agents on his tracks, Indy just gets on the commercial flight to Morocco the same evening without the slightest problem.
Stupidity: When Voller's van arrives at the airfield, the mechanic shot by Gunther acts as if some strangers have arrived, although in the airfield there is a big Nazi plane, Nazi soldiers, and all the people there work for Voller (as it's shown when plenty of men open the hangar's door). Strangely, the mechanic seems to never notice any of these things.
Answer: It was never explained and seems impossible that anyone could survive such an impact. My own thought was the scene was deliberately exaggerated to appear as if Voller was killed in order to fool and then surprise the audience when he later turns up alive. I also thought it looked as if he hadn't aged. Voller may have been much younger than Indy, possibly as much as 25-30 years. When Voller reappears in the 1960s, he looks more like actor Mads Mikkelsen's actual age. The film should have made him look younger at the beginning. There's a lot of "suspension of disbelief" here.
raywest ★