"......its the governor linkage that they loosen the nuts on."
Which should only cause the N2 to run down to the lower end of the governed range.
"....loosening the nut on the throttle-control linkage bolt so it can slip out."
Would have no effect at all, as the the lever on the FCU is sprung-loaded to hold it in the full open position.
Films eh? Never let the truth get in the way of a good story...........
Maybe it's me that should get out more.
TRC