Accidentally found this a while ago before I stopped running stairway, but never posted a forum covering it. So obviously the chance of a floor being empty or containing an anomaly is a 50% chance (With each individual anomaly on an anomaly floor having its own percentage.) However if you get 2 consecutive floors with anomalies or nothing, then the 3rd floor will always be the opposite (nothing for 2 anomalies in a row and an anomaly for 2 empty floors.) I have even had anomalies show up on a third floor after 2 consecutive anomalies, yet when I turned around it sent me back to 12th floor (also walked through the third consecutive anomaly and it went to next floor.) After the third floor the % chance goes back to normal. This is obviously great for Any% as after doing 2 instant turns and getting anomalies, you will know you can run through the next floor with no repercussions. Can also be semi useful for Find anomalies as after 2 anomaly floors you will know the next is empty, but in the rare event you get an anomaly on the 3rd floor and you walk through could make its leaderboard placing controversial