Simple logic to this one ...
There were people behind the barriers and the Mustangs did what they always do and crashed into the barrier trying to run over the people. Once the first Mustang hit the barrier, the people scattered and the following Stangs got confused and ran into each other.
Happens every Mustang Week and most cars and coffee events when more than a few Mustangs are corralled together with people standing on the side of the road.
99 Chevrolet Camaro Z28 M6 - 6.676 @ 103 in 1/8, 10.512 @ 130.2 on street tires, H/C/I
93 Eagle Talon TSI AWD 5spd - Built 6 Bolt, 16G Evo3, HKS 272 Cams - under construction