Used by the routine at CHARACTERS_ACT.

Four bytes, then a 2-byte fallback if bit 4 is set. With bit 0 clear they are the action code and its two objects, tried as the character's own sentence. With bit 0 set, bytes 1 and 2 are the address of a routine instead: it is run once with printing off as a test, and only if it reports success by setting SUCCEEDED is it run again for real.

A step that succeeds with bit 5 set is used up: the LD (IX+$00),$00 near its end writes zero over its own first byte -- IX is the step, not the character's slot -- so it never calls its routine again. The character goes on as before. Only Thorin's remark about the small curious key has the bit. Tried in the simulator: Thorin took the key, said his line the next turn, and went on following the player, his slot unchanged, while the step's first byte went from $23 to $00. The scripts are not among what a new game copies back, so the step stays spent until the game is loaded again.