Who says they were low on gas? The PIC can declare min/emer fuel anytime he wants, a long ways away from the airport.
Unless you stick your head in the cockpit and check the gas gauge you won't really know. If they declared emer fuel, and burnt into the minimum fuel required, they'll get nailed, as the emer fuel call generates reports, and scrutiny.
The Ryan Air Capt's might be more aggressive than others and simply assured traffic priority once it appeared approach control was having a hard time.