Defending vault system

I request a change defending the safe deposit system.
Currently, Immortals have to wait in front of the safe for about 1 to 2 hours to defend the safe.
The reason is that it is too easy to block the guards of the shadows, and very few shadows can get to the 4th floor of the safe.

The part I’m suggesting is to change the immortals’ safe entry waiting system just like the battlefield so that it randomly enters 4 people.

With the current system, the Immortals’ vault defenses have no choice but to run like a very old-fashioned game system.
We can spend money and time on the game, but that part of the time is very inefficient. Please consider it once.