They pulled the leg 1 runners off the course at the exchange point. The exchange zone was in the parking lot where you entered the race track. They had a DJ a scaled down version of the finish line and then had 6-8 chutes set up. When you saw your teammate exit the course and turn into the park lot area there was about a 200 yard straight away, runner 2 moved up to the front of their chute and could tag/hug/whatever after their teammate finished teammate. Runner 2 then ran around a short loop and back along the straight away. Once you merged back with the marathon course, the actual start of the leg was a timing mat about 50 yards further up.