How to edit a scene from the middle of the game story?,How to continue editing from middle of the scene?

Hello I have a question.
I have a game sequence as follows

  1. My game starts with a car driving (for 15 secs) until it reaches its destination then the car crashes. After that the player gets out of the car and starts discovering the environment.

  2. The player triggers a certain point and is attacked by the enemy

  3. The player kills the enemy and the gate opens

My question is, if I want to skip all of those beginning scene steps and jump to the point where the car is already crashed on the destination, the enemy is dead and the gate opens so that I can continue editing my game then how do I directly reach there?

Also for example, if the GTA developers want to edit the 10th mission of the game without playing from the beginning then how would they do?

I have tried Scene management but I was unable to succeed. I have a large map and loading that map on every scene is slow.

Please help me!

hmm kinda complex it sounds eh? there’s obviously a check to see if each of those things have happened right? make a function to override all of them at once and then switch to the scene you want with

SceneManager.LoadLevel() 

or

SceneManager.LoadLeveAsync(); 

after all the variables have changed aka last line in the method should be the scene change. this can be accessed via a KeyCode input in the update during testing in the editor. you can leave the code in and have a

"#"If UNITY_EDITOR 
    // some code 
 "#"endIf 

to hide it.