Halo 5 Mission 13 Easter Egg

I was going through halo 5 on legendary. I was playing mission 13 and right after I beat the first warden I was heading towards the crashed pelcan but instead of heading right, where the two wardens spawn I went left to where there was a locked building and to my surprise I found the arbiter scared armor on the floor and out of no where a wave of enemy spawn. I couldn’t figure out what happened because I kept dying so I progressed on with my mission. If any one has any info or wants to figure it out with me let me no my gamertag is Poptart OG.

I tried finding this, and it looks like the “armour” is just a dead crawler body. Still, pretty interesting. I’m trying EVERYTHING (literally) to see if the door is even able to be opened, but not very expectant.