Dr. Chimps, you do know your movie stuff well .... Yep, that Merry Go Round was in "The Sting" as well as many other second rate/featured films of the 50's, but I think that the actual office scene was built in the studio, and what appears to be an office in the building is actually a storage space. How the hell did you recall the character's name ...... Henry Gondorff?
Actually, the first movie I thought of was Hitchcock's 'Stranger's on a Train' where the baddie buys it at the end on the merry-go-round, but the office clue was key. That's where Redford comes across a hungover Newman and The Sting to get Robert Shaw gets hatched. Both superb movies.