1st method Edit
Discovered by Acryte
Go to the spirit trial. Pull/push the armos statue closest to the door on the right all the way to the wall and move it 2 more paces closer to the door. Now face the armos statue and the wall at a 45 degree angle and jumpslash and you will end up in the unloaded main room. Now just navigate your way to the bridge and find the entrance to the tower.
2nd method Edit
Discovered by ZeldaXMaster
Go down to the bottom of the main room. Go to the right side of the tower but near the left side of the edge of it. Now use a 2 bomb staircase hover towards the tower then do a 3rd backflip and you should hit the loading zone and enter the tower.
3rd method Edit
Discovered by ZAR
Go to the water trial, bait a Freezzard to come extremely close to the door, use the hookshot clip on the Freezzard to get into the main lobby unloaded.