Kunazan’s Shrine advice requested.

[Segev]

This will have spoilers for part of Tomb if Annihilation. You have been warned.

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If the door slams shut after the party triggers that with the (in)correct action, the module discusses the difficulty of picking the lock from inside the shrine. Should the stone key open the lock without difficulty from inside? Or should it not work and picking the lock be required?

[Expired]

This is my personal opinion, but when I DM, I like to add as much realism as possible while still maintaining the feel of magic being able to manipulate the laws of nature. Keys (physical in this case and not magical) are cut to match a specific lock and unless I am mistaken, it is impossible to unlock a door from the inside using a key--not only because there is no keyhole on that side, but also because the key would have to be symmetrical to be able to activate the tumblers from either side. I would rule that they need to make a Thieves' Tools (Dex) check.

[Quietus]

This is my personal opinion, but when I DM, I like to add as much realism as possible while still maintaining the feel of magic being able to manipulate the laws of nature. Keys (physical in this case and not magical) are cut to match a specific lock and unless I am mistaken, it is impossible to unlock a door from the inside using a key--not only because there is no keyhole on that side, but also because the key would have to be symmetrical to be able to activate the tumblers from either side. I would rule that they need to make a Thieves' Tools (Dex) check.

I would agree with this, barring the possibility that the key is itself magical. Either it needs to physically fit the lock and will not work from the inside, or it is a very specific item allowing them to bypass what is functionally an Arcane Lock spell.