Taking the role of the plant security chief, I'd have ventilated those helicopters and anyone who survived the crash.

Plant security vs. NJPD? Raise a cup of coffee and a donut in their memory. Uniforms can be "borrowed" and helicopters can be stolen.

You may not cause a nuclear incident with a pair of helicopters, but given that the connection between the plant and the outbound AC power lines is the single weakest link in the chain between source and consumer, those choppers dropped in the right spot could have cause massive disruption to a large area without so much as a REM or RAD to show for it.