If the Qatari really had 5 min of fuel remained, for some reasons the Qatari went around on the final approach, even the Juneyao gave way, the Qatari would be doomed.
It doesn't really matters if QR had or not 5' fuel!
The bible of radio communications at least in a JAR environment (CAP 413 Radiotelephony Manual) state:
'As soon as there is any doubt as to the safe conduct of a flight, immediately request assistance from ATC. Flight crews should declare the emergency situation early; it can always be cancelled.'
... priority must be given to the distress call! I don't think there are any doubt about it!
Now, if one ATC controller has to control two or more distress aircraft ... in minimum fuel, emergency fuel scenario ... the rules is 'first come, first serve!' unless the crew clearly announce the flight time remaining.