Event edit questions

I'm trying to figure out camera movement, and other things. Fiddling with the introduction scene -- the "Long ago, the War of the Magi..." is giving me some info but it's still unclear how some things work.

This is the byte sequence for the camera while the 1st bit of text, "Long ago [...] ceased to exist", is being displayed over the Narshe peak --

30 04 9E 9E 86 FF

30: Begin action queue for character $30 (Camera)
04: ???
9E: Move vehicle/entity down 8 tiles
0E: Move vehicle/entity down 8 tiles
86: Move vehicle/entity down 2 tiles
FF: End queue

Firstly, i'd like to know what the second byte (04) does; it's not included in the event dump file by Imzogelmo.

Second, how does the movement bytes work? I've changed the last one (86) a few times and the effects were as follows:

84        Move vehicle/entity UP 2 tiles
85        Move vehicle/entity RIGHT 2 tiles
86        Move vehicle/entity DOWN 2 tiles
87        Move vehicle/entity LEFT 2 tiles

What is the logic here? It's like adding 01h changes the movement direction by 90° clockwise. But that doesn't explain much.

Any ideas?