MovieChat Forums > Dial M for Murder (1954) Discussion > People asking about the keys...

People asking about the keys...

posted 9 years ago by Matt_Layden
6 replies | jump to latest

I have a similar question that in my mind leads to a plot hole in the film.

After the inspector switches coats and hides upstairs, Tony leaves the apartment...but doesn't lock his door? Then the inspector comes back downstairs and uses Tony's key to enter it.

This wouldn't make sense because:

A: Tony would have locked the door, or at least tried to and find out his key was the wrong one.

B: If he decided to leave it unlocked, then the key the inspector used wouldn't have been used, yet he uses it to unlock the door.

I say this is a plot hole because it would change the outcome of the ending. He wouldn't have been caught. Yet, they ignore this element.

I tried to explain this away with the door locking on it's own, but we see numerous times from the inside of the apartment, that this is not the case with that type of lock.

Anyone care to explain something I might have missed?

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[–] david_hokey_16 9 years ago

It's simple: just because he left doesn't mean he locked the door. It doesn't show him doing so. The inspector could've used the key reflexively even with the door being unlocked. This makes sense though it probably isn't the answer you want.

[–] yurenchu 9 years ago

It's been a while since I've seen the movie, but I think the following simple explanation applies:

One doesn't need a key to open a door because one can simply turn the door lever handle/door knob when one approaches the door from the inside. However, when one approaches the door from the outside, one does need a key, even if the resident had closed the door but not fully locked it (by turning the key) when he left the house: the door knob at the outside isn't movable.

EDIT: I just rewatched some scenes from the movie on youtube. The door knob is a fixed (i.e. non-turnable) door knob on both sides of the door (inside and outside). But there's a lock right above the door knob, and it's similar to the ones in the following pictures:
- door lock, for a door that opens outward:
http://stat.homeshop18.com/homeshop18/images/productImages/179/godrej-ultra-twin-bolt-1ck-outside-opening-rim-lock-door-medium_4578a544c7bfb7ba8a26fd99b6159348.jpg
- door lock, for a door that opens inward:
http://www.godrejlocks.com/godrejlocks/ProductImages/RIM-LOCK-2C-(Inside-Opening).jpg

As you can see, the locks in these pictures are double bolt locks, each lock has two bolts: the upper "triangular-shaped" bolt is a spring bolt, while the lower "rectangular-shaped" bolt is a deadbolt. I'm not sure if the lock in the movie was also a double bolt lock, or if it only had the spring bolt (which can be locked in place by turning the key). Anyway, when Tony Wendice leaves the house without turning the key to lock the door, he leaves the door closed with only an unlocked spring bolt engaged.

From the outside you'd still need the key to move the spring bolt [*], but from the inside you can simply pull the lever at the righthandside of the lock (provided that the bolt was left unlocked).

So it's not a plothole, you're just not acquainted with this type of door lock systems.

[*] Or you can tinker with a credit card inserted between the door and its post; which is a method that thieves often use in movies.

______
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http://youtu.be/VI57QHL6ge0

[–] hobnob53 9 years ago

I think it is a lock that locks automatically when you close the door, but need a key to re-open. That simple.

He just left and walked out the door. He made no attempt to lock it. Nor is there any indication he left it unlocked (in which case why try the key?) or that this is a plot hole. There may be a small gap in the narrative but no plot hole.

[–] yurenchu 9 years ago

I think the issue that the OP couldn't understand is this: if the lock automatically locks when the door closes, why didn't Tony ever need to use a key to (re)open the door when he was leaving that living room?

It seems the OP just didn't realize that the door was not simply an interior door (such as, for example, a bedroom door) but actually the front door to their apartment (so it doesn't have turnable doorknobs/levers on either side), and that the lock contained a spring bolt that wasn't connected to any doorknobs. This spring bolt, when left unlocked, can be opened/disengaged easily from the inside without a key, but it always requires a key when you want to open the door from the outside.

______
Joe Satriani - "Always With Me, Always With You"
http://youtu.be/VI57QHL6ge0

[–] hobnob53 9 years ago

You mean, you think the OP thought they needed a key to leave the room? Now I'm getting confused!

But you may be right. The lock obviously locks automatically when you close the door (from the outside or inside). There's no lapse or gap or plot hole in Tony's use of his key.

[–] yurenchu 9 years ago

You mean, you think the OP thought they needed a key to leave the room?

Yes, I think that may be what the OP thought, because the OP wrote:

"I tried to explain this away with the door locking on it's own, but we see numerous times from the inside of the apartment, that this is not the case with that type of lock. "

The OP must be referring to the numerous times that Tony and/or Margot opened that door from the inside (i.e. from the living room), without using the key. OP seems to think that the door has a lock similar to this, in which the spring bolt (a.k.a. latch bolt) is connected to turnable doorknobs/handles on both sides of a bedroom door:
- http://g01.a.alicdn.com/kf/HTB17BoDHFXXXXblXVXXq6xXFXXXw/2-Pieces-Door-lock-interior-door-locks-European-style-bedroom-solid-wood-door-handle-locks-Support.jpg

If the above lock is locked from the outside, you'd need a key to open the bedroom door from the inside. If you don't need a key to open that bedroom door from the inside, it means that bedroom door has not been locked and anyone standing on the outside can also open that door without a key. The OP seems to apply the same logic to the apartment door of the Wendices.

But you may be right. The lock obviously locks automatically when you close the door (from the outside or inside). There's no lapse or gap or plot hole in Tony's use of his key.

The latch/spring bolt of the lock is automatically engaged but not automatically locked by closing the door; so it can simply be retracted by pulling the latch handle from the inside of the apartment. There's no such latch handle at the "outside"-side of the door, hence from the outside you can only retract the latch/spring bolt by inserting and turning the key.

The door is automatically "locked" by the latch, but the latch itself is not automatically locked; this ambiguous meaning of the word "locked" may be what confuses some viewers.

And there's indeed no lapse or gap or plothole in Tony's use of the key.

______
Joe Satriani - "Always With Me, Always With You"
http://youtu.be/VI57QHL6ge0