Flaky test mecha_damage: Cannot read null.see_invisible

[github-actions]

Flaky tests were detected in this test run. This means that there was a failure that was cleared when the tests were simply restarted.
Failures:

mecha_damage: [05:02:53] Runtime in code/modules/lootpanel/contents.dm,28: Cannot read null.see_invisible
proc name: populate contents (/datum/lootpanel/proc/populate_contents)
src: /datum/lootpanel (/datum/lootpanel)
call stack:
/datum/lootpanel (/datum/lootpanel): populate contents()
/datum/lootpanel (/datum/lootpanel): on searchable deleted(floor (/datum/search_object), 0)
floor (/datum/search_object):  SendSignal("parent_qdeleting", /list (/list))
qdel(floor (/datum/search_object), 0)
floor (/datum/search_object): on item moved(the floor (127,126,8) (/turf/open/floor/iron), John Doe (/mob/living/carbon/human/consistent), the floor (126,126,8) (/turf/open/floor/iron), null)
the floor (127,126,8) (/turf/open/floor/iron):  SendSignal("atom_entered", /list (/list))
the floor (127,126,8) (/turf/open/floor/iron): Entered(John Doe (/mob/living/carbon/human/consistent), the floor (126,126,8) (/turf/open/floor/iron), null)
John Doe (/mob/living/carbon/human/consistent): doMove(the floor (127,126,8) (/turf/open/floor/iron))
John Doe (/mob/living/carbon/human/consistent): forceMove(the floor (127,126,8) (/turf/open/floor/iron))
John Doe (/mob/living/carbon/human/consistent): forceMove(the floor (127,126,8) (/turf/open/floor/iron))
/datum/unit_test/mecha_damage (/datum/unit_test/mecha_damage): Run()
RunUnitTest(/datum/unit_test/mecha_damage (/datum/unit_test/mecha_damage), /list (/list))
RunUnitTests()
/datum/callback (/datum/callback): InvokeAsync() at code/modules/lootpanel/contents.dm:28