diff --git a/code/modules/mod/mod_activation.dm b/code/modules/mod/mod_activation.dm
index 3982e28621d..170a62519f4 100644
--- a/code/modules/mod/mod_activation.dm
+++ b/code/modules/mod/mod_activation.dm
@@ -267,6 +267,7 @@
 		part.cold_protection = NONE
 		part.alternate_worn_layer = part_datum.unsealed_layer
 	generate_suit_mask()
+	update_speed()
 	wearer.update_clothing(part.slot_flags | slot_flags)
 	wearer.update_obscured_slots(part.visor_flags_inv)
 	if((part.clothing_flags & (MASKINTERNALS|HEADINTERNALS)) && wearer.invalid_internals())
diff --git a/code/modules/mod/mod_control.dm b/code/modules/mod/mod_control.dm
index 0d611d38671..a4e75c25ebf 100644
--- a/code/modules/mod/mod_control.dm
+++ b/code/modules/mod/mod_control.dm
@@ -699,8 +699,11 @@
 	wearer.update_spacesuit_hud_icon(state_to_use || "0")
 
 /obj/item/mod/control/proc/update_speed()
-	for(var/obj/item/part as anything in get_parts())
-		part.slowdown = slowdown_deployed / (length(mod_parts) - 1)
+	for(var/obj/item/part as anything in get_parts(all = TRUE))
+		part.slowdown = slowdown_deployed / length(mod_parts)
+		var/datum/mod_part/part_datum = get_part_datum(part)
+		if (!part_datum.sealed)
+			part.slowdown = max(part.slowdown, 0)
 	wearer?.update_equipment_speed_mods()
 
 /obj/item/mod/control/proc/power_off()