1 - A doorway that was completely boarded up by a large piece of wood near spawn. I went back to that same doorway later during my exploration of the map and the wooden board was no longer attached to the doorway and was laying on the ground.

2 - The sound of someone sobbing coming from the other side of the boarded up doorway. Sobbing stops once the wooden board is laying on the ground.

3 - A black figure moving behind the middle pillar in the room with the three pillars down the middle.

Feel free to post your own findings below.