That is an expanding fire pillow, also known as firebrick. It is used to create a fire block where holes in fire-rated walls are made and prevents lab fires from spreading rapidly to adjacent labs. I had to pull cable from B254 to our labs on either side during a rather narrow window of time. Some of the cable holes are partially blocked, making it difficult to reach the cable to them. The cable is then just guided to the hole from a distance. With no help, it's not possible to see this material getting shoved out of the hole. I can assure you that I took great pains not to allow the CYMAC coax to fall into any equipment, or drag against any other cables.