The pilot must comply with ATC instructions.
Actually no. That is one of the byproducts of declaring an emergency.
The reg's allow me to do as I need. Most of the time during an emergency ATC is one helluva an asset to have. Sometimes it's a detriment and the PIC does what is necessary. He or she will have to answer for it and others will pass judgement (and not the type passed here)
My speakers are deferred right now so I cant listen to the tapes, as such I'm talking in general terms.
While most of the time we're all on the same page of music, there's situations where ATC's priorities and the crews differ.