The cab scene
This probably sounds silly, but something has always bothered me about this scene. When Zeus and McClaine are following the ambulance, Zeus mentions how if McClaine had said Wall Street, they could follow it all the way. McClaine tells him that that's a different hospital. As McClaine is explaining this, you hear Zeus say "Oh," before McClaine even finishes the sentence. Then McClaine mumbles, "St.Lukes," and looks at Zeus who then looks back at him.
Was this just a bad cut/overdub? That whole exchange just seemed off somehow or out of sync.