I know this is a little late as you have already posted other videos .... bit I am fairly sure that you do not need to cut the chain? just loosen off the adjusters and remove the wheel spline and then the chain can be removed off the sprocket, it can hang loose until you come to refit the wheel back? ... as an aside, do you have a link to the jack please?

Great videos. Did you manage to grind off riveted link and fit a master link or did you get a new chain? Thanks