The eastern door closes on entering the room, making it impossible to backtrack back to Ice Armos (and the Big Key Room)

Going from the east door to the stairs, the fastest way through the room is to dash left and then dash up into the stairs. Dashing left immediately from the doorway is not possible due to the collision of the torches; you'll need to move up at least one pixel to safely clear the torch, but 8 is optimal (moving up for 4 frames before starting a dash-turn, getting from 0378 to 0370).

Since the door is a shutter door, Link will be fully out of the doorway after the screen transition, and can move directly upwards (even wall-pumping for a few frames, in theory).

Using the hookshot on the edge of the torch can potentially save a couple of frames, but otherwise these three strats for opening the crack in the north wall are nearly identical.

As with all cracked walls of this type, doing another dash after bonking can save up to 5 frames and is recommended to go for.