Auto protect certain columns after 5 minutes inactivity

[SKuser]

Hello!
I have prepared a document in which about 50 volunteers must indicate their availability on certain dates each month. The columns in which they indicate yes or no should always open for editing, for anyone.
In contrast, columns A through L contain information they should never be able to edit. Only my office colleagues are allowed to edit this. Therefore, these columns should be password protected.

I would like to set the following:
When someone unprotects columns A through L with the password, this protection should be automatically restored after 5 minutes. One must then manually unprotect it and after another 5 minutes the security is restored again. Etc. Etc.

Why: Colleagues will forget to restore column security manually. We know from experience that our lovely volunteers are enormously quick to ruin the entire file (unintentionally) when everything is open for editing, so automatic security is very important

I know how and where to enter the code, but I cannot write any code myself. Hopefully someone can help me. Thanks in advance!!!

 

[SKuser]

Also, if I set it to protect after 5 minutes, what happens when someone closes the file within those 5 minutes? Will it then be unprotected, or will it also restore protection when the file is closed?