I was looking through the games scripting files for the mission Keyes. I found a few interesting things that were scripted but never linked to anything, including some scripted banshee flight paths for when you are fighting in the exterior.

But I also found what looks to be what I believe is an easter egg that was never completed, and possibly Bungie's first attempt at "achievements"

(script dormant i_am_skin_diver
(ai_place med1_flood )
(object_set_permutation (list_get (ai_actors med1_flood )0 )"head" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )0 )"left arm" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )1 )"" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )2 )"" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )2 )"left arm" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )3 )"" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )4 )"right arm" "~damaged" )
(object_set_permutation (list_get (ai_actors med1_flood )4 )"left arm" "~damaged" )
(sleep_until (= 0 (ai_living_count med1_flood )))(set skin_diver true ))

(script dormant more_blood_for_me
(sleep_until (> (ai_living_count enc5_7_cov/specops )0 ))
(sleep_until (= 0 (ai_living_count enc5_7_cov/specops )))
(sleep_until (> (ai_living_count enc7_1_cov )0 ))
(sleep_until (= 0 (ai_living_count enc7_1_cov )))
(sleep_until (> (ai_living_count enc7_3 )0 ))
(sleep_until (= 0 (ai_living_count enc7_3 )))(set bloodthirsty true ))

(script dormant award_ceremony
(if skin_diver (print "skin diver medal awarded!" ))(if bloodthirsty (print "bloodthirsty medal awarded!" )))

To translate this to normal terms, the first script (i_am_skin_diver) spawns a group of AI, and sets them to all be missing limbs, when they are all dead it sets a condition to be true. The second one (more_blood_for_me) looks to be checking if all the specop quads, plus some other elites have been spawned and then killed, and sets a second condition to be true. The last script (award_ceremony) if called upon (it isn't) would print to the screen on debug machines that a medal would be awarded.

Now none of these are called upon, except for the "skin diver" which would place maimed flood in certain coolant pools, but before released Bungie set the spawn counts to zero, and even if spawned killing them would ultimately do nothing to the player.

So what does all this mean.... well nothing in the end. But it's still fun to see some of their early ideas for "medals" or "achievements" even if it never made it past their own internal tests.

I'll keep updating this if I find anything else out. As far as the cut banshee flightpaths, I successfully restored those into the mission.