Did you read the article? How much context and background do you want?!...
"Thai Airways flight TG408, travelling from Singapore’s Changi Airport to Bangkok’s Suvarnabhumi Airport, transmitted a squawk 7700 distress code mid-flight, an alert used to indicate an urgent situation requiring immediate assistance.
According to reports from flight tracking service Flightradar24, the emergency signal was sent while the aircraft was over the Gulf of Thailand. Despite the alert, the plane landed safely at Suvarnabhumi Airport at 20:34.
It has now emerged that the distress call was prompted by a medical emergency on board. Reports suggest that a passenger suffered cardiac arrest, prompting the crew to request priority landing in an effort to provide urgent medical attention upon arrival".