Click the + icon in the bottom right, it will add a new event and you can place any gameobject which may have a script with a public method you want to call.
In this case I have added the door object, this has a script called DoorController which has a public method called OpenDoor
You can then run this code each time you unlock something, this can be changed on each door, and multiple events can happen in each
Event Example
In the example below you can see the event opens from the script DoorController
The DoorController exists on the door object itself.
Stopping Keypad Interactions
I have also added a RemoveTag script in case you want to remove the tag to stop interaction with the keypad once you get a specific code. (This stops you from interacting with keypads after, if you wish)