diff --git a/code/modules/mob/living/living_movement.dm b/code/modules/mob/living/living_movement.dm
index b2d222b25cb..b92b2654f78 100644
--- a/code/modules/mob/living/living_movement.dm
+++ b/code/modules/mob/living/living_movement.dm
@@ -29,7 +29,7 @@
 	add_movespeed_modifier((m_intent == MOVE_INTENT_WALK)? /datum/movespeed_modifier/config_walk_run/walk : /datum/movespeed_modifier/config_walk_run/run)
 
 /mob/living/proc/update_turf_movespeed(turf/open/T)
-	if(istype(T))
+	if(isopenturf(T))
 		add_or_update_variable_movespeed_modifier(/datum/movespeed_modifier/turf_slowdown, multiplicative_slowdown = T.slowdown)
 	else
 		remove_movespeed_modifier(/datum/movespeed_modifier/turf_slowdown)