Looks like a masonic ring.. Red is the color of fire, and fire was to the Egyptians the symbol of the regeneration and the purification of souls. Hence, in the Masonic system, red javascript:void(0)is the symbol of regeneration. Thus red is the color assigned to the Royal Arch Degree since that degree teaches the regeneration of life. Adrenochrome bastards! Or maybe is is just one of the "mood rings" from the late 70's  lol Seriously, maybe the  person on the stretcher came up from the tunnels