What about a Fast Forward?
Team would bypass all of these tasks, hence not being seen by the eye witness
That could also explain why 8 blue structures were set up, if they were later in the leg- production would be aware that a team completed the FF, and they no longer needed to set the extra structure
That would make it leg 3, which would ease up the timeline
The other options speculated seem... unprecedented
There’s only ever been one other double elim, and that was following a first leg non-elim; it was not a popular twist
The injury theory is plausible, but I rather hope not