With acknowledgement to Avherald
A Volaris Airbus A321-200, registration XA-VLV performing flight Y4-737 from Guadalajara to Mexico City (Mexico), was on final approach to Mexico City's runway 05R when the first officer fainted. The captain declared Mayday and continued the approach for a safe landing on runway 05R.
Hmmm.....Mayday? Maybe more effective to tell ATC to get a doctor/ambulance to the aircraft immediately on parking, and why?
A Mayday call can create unnecessary distractions, in some circumstances. In this case there was only one priority, and that's to get treatment started on the F/O. Apart from him, it's arguable that there was no immediate threat to life.