Continuity mistake: Marion's shoes change when in the museum, from heels to flats.
Revealing mistake: Younger Tom dropped his policeman's jacket onto the "fire" and when Younger Marion came over to the fire (almost 30 seconds later), the jacket still had not caught on fire. The next time the jacket was shown, most of it still looked unscathed by the fire. (01:33:30 - 01:35:36)