Sorry for the delay! Took a while to figure out what Trevor/Chris did in Prague after the telephone Roadblock (which might also explain their elimination).
As noted
here, teams were directed to Romantický Hotel U Raka after the Roadblock. Trevor/Chris decided to travel by metro from Dejvická Station to Mustek Station, switching to a taxi there.
The problem is Mustek Station is on the other side of the river and
nowhere near where they needed to go! Dejvická Station is already the closest station to Romantický Hotel, which is just 1.5km/0.9mi away. The extra time they took would have cost them around 40min, squandering their chance to jump ahead of Jessica/Cody, who were stuck finding a taxi.