replaces explosive mines with (new) sentry mines

code/game/area/depot-areas.dm

@@ -31,6 +31,7 @@
 	var/detected_mech = FALSE
 	var/detected_pod = FALSE
 	var/detected_double_agent = FALSE
+	var/mine_trigger_count = 0
 	var/obj/machinery/computer/syndicate_depot/syndiecomms/comms_computer = null
 	var/obj/structure/fusionreactor/reactor
 
@@ -81,9 +82,9 @@
 	detected_mech = FALSE
 	detected_pod = FALSE
 	detected_double_agent = FALSE
+	mine_trigger_count = 0
 	updateicon()
 
-
 	alert_log += "Alert level reset."
 
 /area/syndicate_depot/core/proc/increase_alert(reason)
@@ -119,6 +120,12 @@
 	if(on_peaceful)
 		increase_alert("Vandals!")
 
+/area/syndicate_depot/core/proc/mine_triggered(mob/living/M)
+	if(mine_trigger_count)
+		return TRUE
+	mine_trigger_count++
+	increase_alert("Intruder detected by sentry mine: [M]")
+
 /area/syndicate_depot/core/proc/saw_mech(obj/mecha/E)
 	if(detected_mech)
 		return

code/game/objects/effects/mines.dm

@@ -53,6 +53,15 @@
 	if(isliving(victim))
 		victim.Weaken(stun_time)
 
+/obj/effect/mine/depot
+	name = "sentry mine"
+
+/obj/effect/mine/depot/mineEffect(mob/living/victim)
+	var/area/syndicate_depot/core/depotarea = areaMaster
+	if(istype(depotarea))
+		if(depotarea.mine_triggered(victim))
+			explosion(loc, 1, 0, 0, 1) // devastate the tile you are on, but leave everything else untouched
+
 /obj/effect/mine/dnascramble
 	name = "Radiation Mine"
 	var/radiation_amount

code/game/objects/effects/spawners/random_spawners.dm

@@ -170,7 +170,7 @@
 /obj/effect/spawner/random_spawners/syndicate/trap/mine
 	name = "50pc trap landmine"
 	result = list(/datum/nothing = 1,
-		/obj/effect/mine/explosive = 1)
+		/obj/effect/mine/depot = 1)
 
 /obj/effect/spawner/random_spawners/syndicate/trap/documents
 	name = "66pc trapped documents"