I tested it for a bit, with a little lineup it can be done even faster than on your video. You can drop all the way down without taking any damage. However, as I expected, your progress gets stalled by your brother and his endless battle with the enemies up there. From below it's much harder to dispatch of them quickly and even if you hit the checkpoint, your brother will make no progress. I'll give it some more testing time when I have the time for it myself, if there's any way to rubberband your brother, it will be a nice time save. Have a good day!

Hey! Nice finds, however the one in chapter V will definitely be slower as you ideally want to kill all the enemies before your brother starts shooting at them as that will stall his progress in walking towards the town. Mayyyybe you can snipe them all out as Thomas and then take this route but I still think the benefits are minimal at best.

Golden rangers? Is that allowed?