The John Nance drill is based on the death of John Nance of the Columbus (OH) Fire Department. Engineer John Nance was trapped in the basement of a commercial occupancy following a floor collapse. Despite the exhaustive efforts of multiple crews, Engineer Nance was unable to be removed from the occupancy prior to succumbing to the fire and its by-products. Several attempts were made in John's rescue attempt, including dropping a ladder in the hole for him to climb out. Unfortunately, John was too disoriented to complete his own extrication from the below-grade area.
Dozens of videos on-line.
Lift arm and slide rope beneath arm. (Dashed section of line)
Lift other arm and slide rope beneath that arm.
If rope is tied in a loop, take end of loop opposite end draped over chest. Slide beneath loop draped over chest. Pull end of loop that was slid beneath chest loop in direction you wish to drag the unconscious body.
In a similar way, a guy as strong as Chernovsky could use a much shorter loop to make a field expedient grab handle to drag bodies to the porch.
The loop could be untied and pulled from one end to remove. In Chernovsky's case, he would simple slide the end of the loop he grabs back beneath the chest loop.
Wait until Wednesday to see how well it works for them.