Answer: Amok
Explanation:
Amok is a psychic behavior that is unruly and characterised by feelings of unrest followed by a desire to kill. It is usually practised in South eastern Asian Culture, but recently it has been associated with mental disorders which the individual may not even realised he carried out after recovery.
This behaviour, Amok, is a culture bound syndrome was carried out by the man who attacked the market as described by John when he travelled.