Only 30 seconds ? Sure it wasn't 30 minutes.... ?
He didn't crash, but punctured. So, he first lost a few seconds slowing down with the flat tyre. Unlike in a crash, his mec was prepared for the bike change. That costed 10 seconds, pushing included. Reaching topspeed, another 2 to 3 seconds extra timeloss. So, all together, 17 to 18 seconds. Enough to win silver, not enough to win gold. The last part of the race, after a timecheck of his team, Evenepoel knew he had 20 seconds on Ganna and Van Aert. More on Tarling. So, he slowed down, especially in the corners to avoid any risk. Evenepoel confirmed it after the race. No way Tarling could have come close to Evenepoel.