Singapore’s Land Transport Authority has officially classified "waiting for others to exit" as a symptom of a rare, debilitating brain tumour.

Commuters at Jurong East were horrified when Tan Ah Kow stood still for three seconds while the train doors opened.

Witnesses claim Tan exhibited "anti-social" behaviour by not immediately shoulder-checking an elderly grandmother into the platform gap.

"Wah lau, this guy siao or what?" said witness Lim Pek Chee.

"The door open only he just stand there like sotong, wait for what? Give chance for people to go out first ah? This one not Singaporean lah, must be spy!"

LTA confirmed any delay in the boarding scrum will now be met with public caning to restore national efficiency.

"Common sense is a threat to our GDP," a statement concluded.