SCP-087-1 has ambushed the D-class personnel in all of the three reports linked above. The third, who it ambushed from behind instead of from the front, ending up passing out lower down. The peculiar thing is that the creature did not stare at the personnel as it did with the previous two, but instead looked directly at the camera, as if it were looking at those viewing the video feed directly, instead of the intruder. The person from the third report is presumed dead, because she never made it back before the audio and video feeds cut out and was never re-established. It is classified as Euclid, a dangerous SCP that must be watched, instead of Safe, an SCP that can be left alone without being watched, which is strange. While it is dangerous, it is easily avoidable, as, being a staircase, isn't mobile. However, the reason behind this is explained by the forth exploration of the stairwell, but the report is completely censored and left to the reader's imagination. All that is known is that, after the exploration, eerie knocking was heard from the inside of the stairwell's entrance door...