I have to say the controller was extremely professional throughout...the crew on the other hand....!
You can't bully ATC into giving you a different runway by threatening them with an Emergency, you certainly shouldn't randomly decide that you're going to turn left to position for the runway you want....there's more than one a/c out there...
I don't think he actually declared an Emergency at all (technically) ICAO Standard Phraseology requires the use of "Mayday Mayday" or "Pan Pan Pan" to do that...and as for "fuel priorities":
Fuel Reserves Approaching Minimum:
’Fuel Emergency’ or ‘fuel priority’ are not recognised terms. Flight crews short of fuel must declare a PAN or MAYDAY to be sure of being given the appropriate priority.
(Source: ICAO Phraseology Reference Guide)