Lance trigger null runtime

Created by: gbasood

runtime error: Cannot modify null.trigger.
proc name: Destroy (/obj/effect/lance_trigger/Destroy)
  source file: lance.dm,106
  usr: Jakob Jakobsen (/mob/living/carbon/human)
  src: the lance tip (/obj/effect/lance_trigger)
  usr.loc: Asteroid (200,241,5) (/turf/unsimulated/floor/asteroid)
  src.loc: Mineral deposit (199,241,5) (/turf/unsimulated/mineral/random)
  call stack:
the lance tip (/obj/effect/lance_trigger): Destroy()
qdel(the lance tip (/obj/effect/lance_trigger), 0, 0)
the lance tip (/obj/effect/lance_trigger): Crossed(the lance tip (/obj/effect/lance_trigger), 0)
the lance tip (/obj/effect/lance_trigger): forceMove(Mineral deposit (199,241,5) (/turf/unsimulated/mineral/random), 0)
the lance tip (/obj/effect/lance_trigger): forceMove(Mineral deposit (199,241,5) (/turf/unsimulated/mineral/random))
Jakob Jakobsen (/mob/living/carbon/human): lock atom(the lance tip (/obj/effect/lance_trigger), -1, 0, 1)
the lance tip (/obj/effect/lance_trigger): New(null, Jakob Jakobsen (/mob/living/carbon/human), Ancient object (/obj/item/weapon/melee/lance))
Ancient object (/obj/item/weapon/melee/lance): lower lance(Jakob Jakobsen (/mob/living/carbon/human))
Ancient object (/obj/item/weapon/melee/lance): attack self(Jakob Jakobsen (/mob/living/carbon/human))
Jakob Jakobsen (/mob/living/carbon/human): Activate Held Object()
Alone (/client): attack self()
Alone (/client): Southeast()

@unid15