Activating a Fire Alarm within a zone starts a 15-second countdown. The player must evacuate into a Fire Escape door within this time; once the alarm finishes, all Melds on that floor are Incinerated and removed. They are obstacles and hazards that erode and obstruct the entire Stairwell. (Touching rope-like structures opens them briefly.)

A shy, static entity primarily found in the maze sections of the Stairwell. It does not actively pursue the player, usually standing still or moving very slowly. It starts moving if the player gets too close, maintains eye contact for too long, or makes loud noises nearby, so one must maintain distance and pass quietly. It ignores (passes through) Melds that block the path.

A neutral/passive humanoid entity wearing a hood with glowing white eyes. It does not attack the player and functions more like an easter egg NPC that can be approached for conversation. It speaks in a strange language (==-=_-=).

An orange, ball-shaped entity with several brown protrusions on its surface. It suddenly pops out and chases the player when they open a Locker. It deals 5 damage whenever it is stepped on or collided with. The player must time an interaction to grab the approaching Stem and then throw it to make it explode. Defeating it unlocks the 'Get away from me!' achievement.

Appears near turned-on TVs and has the characteristic of mimicking and following the player's every footstep and movement path. If the player stops, Noise stops, but if the distance increases, it rushes forward like a fast-forwarded video to close the gap. It disappears if the TV is knocked over and broken. (Breaking the TV unlocks the 'Rage Room' achievement.)