The medical profession here is famous for allowing foreigners to come here for medical treatments as they pay subsidized rates. Mt. Elizabeth is usually full of the turbaned types from the Middle East. The article already stated that he was coming for other medical reasons and was not symptomatic before getting on the plane. It was found after he arrived in Singapore.
SOME PEOPLE TRY TO TURN BACK THEIR ODOMETERS. NOT ME. I WANT PEOPLE TO KNOW WHY I LOOK THIS WAY. I'VE TRAVELED A LONG WAY, AND SOME OF THE ROADS WEREN'T PAVED. ~ Will Rogers
The ST article about today's numbers has a more full explanation. The Bangladeshi chap had already had two previous operations in Singapore and was having medical complications from that when back home so was granted a waiver for follow up treatment with his original doctors.