Manoeuvring a large aircraft around on the ground at JFK is quite challenging in general with narrow-ish taxiways and numerous 90deg turns. In the BA terminal 7 area there are also nearby obstacles and quite specific stand entry requirements to reduce the risk on hitting anything with your wingtip/outboard engine. Great concentration is required and it's always a relief to shutdown/take off. Aircraft have clouted things there before and will again, this was probably a first for Qantas though.