Good news for awr fans, this split is much less bad now because you can heal for only 0.8 timeloss if you do it here, same elevator climb as the normal strat. Just make sure to press heal as early as possible. I try to press it during lever freeze frames while in mid air
I found this movement for the grub under sanctum, pretty consistently at or under 11 seconds for that room, best being 10.66 (I checked some 107 runs that get this grub entering sanctum and elowen had the cleanest at around 12 sec) and I think I've done it over a hundred times and only had the rava run into me once so it feels much cleaner than going right then up. the wall jump on the small ledge can be a bit awkward, but you can dash into it (but don't hold left until the dash, else you'll dash off it and it goes badly). also, because of the way you aggro the rava, even if you miss the pogo or walljump, you can safely climb the right wall. the two dashes after the grub can be a bit tight, i've found letting go of a direction during the second means i don't overshoot it and fall into the elevator but ymmv. not sure if it applies to other categories/patches (did this on 1578) but maybe? (also yes i should use hktimer i just didn't feel like setting that up today)