In some dungeons, some loading zones to move between certain floors do not require a "loading transition" like a staircase. Sometimes it only requires falling down from one room to the other and other times you can use a block elevator, big spring, or fan to move upwards. They following dungeons all share this unique trait:
The way the game loads rooms and floors in those dungeons is different from the other ones. If you're standing on an elevated area in a room and use the Tornado Rod, Link will gain enough height and enter the loading zone area to be "considered as being in the floor above", but the game will not actually load the floor. That means, when Link falls back down after using the Tornado Rod, he will simply land back where he started.
However, by taking damage while Link is at a high enough point to be considered in the loading zone, it is possible to trick the game into thinking you're actually on that floor and it will load it for you. This works because the loading zones won't activate while Link is in the "Tornado Rod state", so by taking damage it will return Link to normal, thus activating it. The most convenient and common method of taking damage is by using a bomb explosion (hence the name "Bombrod"), however there are some cases were an enemy can be used instead.
† The timing is very precise and takes a long time to get down. If you're using a raiseable wall and standing next to it on lower ground, the correct time to use the Tornado Rod seems to be soon after the 4th red flash.