Not sure where you guys are from but your high-rise pack demonstration and explanation was done very well! Thanks for posting! Be safe and have a Merry Christmas!
I notice that you do not employ a shut off valve in the line. As a rule our brigade always fit a shut off valve in the line in case you need to add more lengths after the line is charged.
I saw the standpipe valve, a gate valve right after the standpipe valve (before the pressure gauge) and then a break-apart tip on the nozzle, so there are three ways they could stop the flow of water to extend the line.