From working with folks in law enforcement, "We proceeded to dinner," makes perfect sense coming out of their mouths. In fact, I wouldn't be surprised to hear them say "10-19 the resturant." (10-19 is the Park Ranger radiospeak at our park for literally "proceed to location.") So I guess if your character was a cop or a Ranger or other law enforcement that still uses the 10-codes it would fit.

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"The Alliance ain't the good guys. They're the opposing faction." ---Sam Shepherd or Stephen Howie

Point taken. Also, when some people give statements to the police they might say "We proceeded to go to dinner", because they're speaking in a manner they believe is correct under the circumstances. Our vocabulary can shift when we talk to officials, doctors, college professors, bosses, etc.