Fixes ash walker speed not updating in some situations (#23378)

code/modules/mob/living/carbon/human/species/unathi.dm

@@ -131,23 +131,19 @@
 		fire.Remove(H)
 	var/datum/action/innate/ignite/ash_walker/fire = new()
 	fire.Grant(H)
-	RegisterSignal(H, COMSIG_MOVABLE_Z_CHANGED, PROC_REF(speedylegs))
-	speedylegs(H)
 
 /datum/species/unathi/ashwalker/on_species_loss(mob/living/carbon/human/H)
 	..()
 	for(var/datum/action/innate/ignite/ash_walker/fire in H.actions)
 		fire.Remove(H)
-	UnregisterSignal(H, COMSIG_MOVABLE_Z_CHANGED)
-	speedylegs(H)
+
+/datum/species/unathi/ashwalker/movement_delay(mob/living/carbon/human/H)
+	. = ..()
+	var/turf/our_turf = get_turf(H)
+	if(!is_mining_level(our_turf.z))
+		. -= speed_mod
 
 /datum/action/innate/ignite/ash_walker
 	desc = "You form a fire in your mouth, fierce enough to... light a cigarette."
 	cooldown_duration = 3 MINUTES
 	welding_fuel_used = 0 // Ash walkers dont need welding fuel to use ignite
-
-/datum/species/unathi/ashwalker/proc/speedylegs(mob/living/carbon/human/H)
-	if(is_mining_level(H.z))
-		speed_mod = initial(speed_mod)
-	else
-		speed_mod = 0