According to a newspaper headline, Steve arrived in London on a Monday and disappeared before reaching customs. Steve spends that day looking for Michael, instead finding Joan and spending that night at her place. The next day, Tuesday, after meeting Joan's boss, they chase around town after Michael and end up in police custody. Later that night they are released and discover Michael's secret hideout and find a coded message about someone leaving the country Sunday at noon, which suddenly is only 9 hours away despite the previously established time line being that it is early Wednesday morning.
When Steve gets to Kingston House, he enters an elevator with two doors that he has to close manually. In the next shot, when he exits the elevator, there is only one door - the inner gate-like door has disappeared - and it opens automatically.
At 2:20 Dr. Halas is snatched and hustled into the back door of a 4-door Chevrolet sedan. At 2:25 they are shown leaving in a two-door Chevrolet coupe.
Obvious stunt double for Clifford Evans (Michael Grand) in the fight with George Raft (Steve Rossi) at the end of the film.
When airport authorities issue the radio call to local police to search for Rossi, he's described as being 5 feet 11 inches tall. George Raft was only 5'7" tall.