Used by the routines at 60626, 62892 and 62976. Attempts to move a character in the following ways, in the given order, depending on the directions that are available at the character's current location:

Move	Condition
Up	There is a step going up in the direction the character is facing
Turn round	There is a step going up in the other direction
Forwards	There is no step going up
Down	The character can only step down from his current location