Option to set an alternative passcode ("double bottom") that either opens a limited set of chats, opens a different account, or destroys one of the connected accounts completely when entered.
Use cases
Could be used by political activists in opressive countries when they are required to unlock their chats.
Potential issues
If such an emergency passcode is set, the app won't be able to use your fingerprints or other biometric data to unlock chats. As a result, the absense of biometric unlock could be used a clear indicator that a person has something significant to hide – and it becomes impossible to prove this is not the case.
This might provide a false sense of security and might actually make the situation worse for an activist's or an innocent bystander.
We can still be able to use the fingerprint, but instead we can just make it point to the account that we want, we can make it so the actual account can be opened only using passcode... This eliminate the problem that you mentioned above... In short we need the ability to set different accounts/action to use only the passcode and one single account to use the fingerprint.
Or by having one set of biometric data (say, the dominant hand’s thumb, so it looks natural) unlocking the “public“ chats and another set (like the other hand’s pinky finger) unlocking all the chats, including hidden ones.
This eliminate the problem that you mentioned above...
In short we need the ability to set different accounts/action to use only the passcode and one single account to use the fingerprint.