your questions regarding the game rules (improving the interpretation).

What if there are no doubts? Dark clearly had no doubts. That is, even if this rule is introduced, it will be difficult to apply.

He wasn't doubting, but that doesn't mean he's right.

By "action" here, we mean interaction with any objects - visiting, collecting, breaking through.

What is meant by "action" is not specified in the rules; for you, it's visiting, collecting, or breaking through, but for me, it's, for example, scouting. Also, stepping on a cell or flying over it is also an action for me.