The M.A.R.C.O unit's panels can malfunction and lock up if and when a M.A.R.C.O unit experiences fear.
The M.A.R.C.O unit will shake and imatate human fear however if not obvious this are preprogrammed emotions and not real, they can be disabled in the audio menu's.
The M.A.R.C.O unit's voice will artifically shake and stutter to to better imatate fear.
Learn about a M.A.R.C.O unit's printing function