Containment Room 5 is the Containment Room designated for the containment of SCP-1499, an anomalous mask capable of sending it's wearers to a different dimension, and SCP-500, 1 of 47 pills that can cure any disease, including anomalous diseases. However, SCP-500 is missing during the containment breach, so you'll have to find it to use it.

SCP-500 is a containment room that can only be accessed with Containment Tier 3. SCP-500 is a room with nothing but an open but empty containment cell, where SCP-500 is meant to be kept.

SCP-1499 is a containment room that can only be accessed with Containment Tier 3. SCP-1499 is an anomalous mask that transports it's wearers to a new dimension temporarily. Most SCPs are unable to hurt the wearer unless they are not wearing the mask.