Security Level subsystem (#58248)

Co-authored-by: Mothblocks <35135081+Mothblocks@users.noreply.github.com>

code/modules/shuttle/emergency.dm

@@ -568,7 +568,7 @@
 	var/obj/machinery/computer/shuttle/C = getControlConsole()
 	if(!istype(C, /obj/machinery/computer/shuttle/pod))
 		return ..()
-	if(GLOB.security_level >= SEC_LEVEL_RED || (C && (C.obj_flags & EMAGGED)))
+	if(SSsecurity_level.current_level >= SEC_LEVEL_RED || (C && (C.obj_flags & EMAGGED)))
 		if(launch_status == UNLAUNCHED)
 			launch_status = EARLY_LAUNCHED
 			return ..()
@@ -588,6 +588,10 @@
 	light_color = LIGHT_COLOR_BLUE
 	density = FALSE
 
+/obj/machinery/computer/shuttle/pod/Initialize(mapload)
+	. = ..()
+	RegisterSignal(SSsecurity_level, COMSIG_SECURITY_LEVEL_CHANGED, .proc/check_lock)
+
 /obj/machinery/computer/shuttle/pod/ComponentInitialize()
 	. = ..()
 	AddElement(/datum/element/update_icon_blocker)
@@ -603,6 +607,20 @@
 	. = ..()
 	possible_destinations += ";[port.id]_lavaland"
 
+/**
+ * Signal handler for checking if we should lock or unlock escape pods accordingly to a newly set security level
+ *
+ * Arguments:
+ * * source The datum source of the signal
+ * * new_level The new security level that is in effect
+ */
+/obj/machinery/computer/shuttle/pod/proc/check_lock(datum/source, new_level)
+	SIGNAL_HANDLER
+
+	if(obj_flags & EMAGGED)
+		return
+	locked = new_level < SEC_LEVEL_RED
+
 /obj/docking_port/stationary/random
 	name = "escape pod"
 	id = "pod"
@@ -698,7 +716,7 @@
 /obj/item/storage/pod/can_interact(mob/user)
 	if(!..())
 		return FALSE
-	if(GLOB.security_level >= SEC_LEVEL_RED || unlocked)
+	if(SSsecurity_level.current_level >= SEC_LEVEL_RED || unlocked)
 		return TRUE
 	to_chat(user, "The storage unit will only unlock during a Red or Delta security alert.")