ACMS, that was my thought- which is why I was asking- is this something taught as an actual ditch procedure (at my airline it sure as heck isn't, probably for the reasons you mention) or is it something from engineering experience with replacing used/unserviceable slides?
I asked because I would be very surprised if any airline taught that method as a procedure to be used in an actual ditching- e.g B737-800, block rear doors and redirect pax to overwing and forward exits. (No mention of taking slide packs to fwd doors for use there)