Add wires/radio Destroy().

code/datums/wires/wires.dm

@@ -48,6 +48,10 @@ var/list/wireColours = list("red", "blue", "green", "black", "orange", "brown",
 			var/list/wires = same_wires[holder_type]
 			src.wires = wires // Reference the wires list.
 
+/datum/wires/Destroy()
+	if(holder)
+		holder = null
+
 /datum/wires/proc/GenerateWires()
 	var/list/colours_to_pick = wireColours.Copy() // Get a copy, not a reference.
 	var/list/indexes_to_pick = list()

code/game/objects/items/devices/radio/radio.dm

@@ -838,4 +838,9 @@ var/GLOBAL_RADIO_TYPE = 1 // radio type to use
 	if(isrobot(src.loc))
 		var/mob/living/silicon/robot/R = src.loc
 		R.radio = null
-	..()
+
+	if(wires)
+		wires.Destroy()
+		wires = null
+
+	..()