I was playing a solo game on voyage of despair when I noticed this door next to the zombie for the anti gravity Easter egg and before the footage I thrown a wraith fire at the door and went up to it and I started hearing very loud knocking/banging. This is to strange for it to be atmospheric ambience as I have been playing voyage since release and have many hours played on the map and I never heard of this before. Just wanted to post this hear to see if anyone else experienced this before.