Bowe Bergdahl said he wanted to leave his outpost, OP Mest, at night and run—or at least walk—to his base at FOB Sharana. As Sarah said in Episode 01, this plan is technically feasible. The distance is about 20 miles. He figured he’d make it there in 24 hours or so. At the time, Bergdahl was a good runner, and he was used to high altitudes from growing up in Idaho.

But we were curious about what this walk would be like. What obstacles would someone face?

This aerial map (push play to fly over the area) gives a sense of the terrain Bergdahl would have had to cross to get from Mest to Sharana.

There are several different routes you could take from Mest to Sharana. There are roads, like Route Audi, for instance—the main road between the two points. Looking at Route Audi on the map, you can see it doesn’t provide much cover. There are mountains to the west of Route Audi. But according to people we’ve talked to who are familiar with the area, that terrain is tricky to navigate and very steep. And then there are villages scattered along the way, where an outsider would be spotted quickly—not necessarily by the Taliban, but word would get out.

At the end of the route, Bergdahl would have faced another tactical challenge: simply getting back onto the base at FOB Sharana. Bergdahl told Mark Boal that he’d thought about that. FOB Sharana (unlike OP Mest) was a pretty active base, he said, with troops, as well as Afghan nationals, coming and going throughout the day. His plan was to walk up to the main gate through the bustle of morning traffic. When he got close, he’d take off the Afghan clothes he was wearing—he would have his Army uniform on underneath—and the guards would see he was an American.