Unity 2D Door-Room Transitions Help

Couple of things:

Thing 1: Photographs of code are NOT A THING. If you post a code snippet, ALWAYS USE CODE TAGS:

How to use code tags: Using code tags properly

Thing 2: Keep in mind that using GetComponent() and its kin (in Children, in Parent, plural, etc) (as well as ALL the Find() flavors, without exception) to try and tease out Components at runtime is definitely deep into super-duper-uber-crazy-Ninja advanced stuff.

This sort of coding is to be avoided at all costs unless you know exactly what you are doing.

If you run into an issue with any of these calls, start with the documentation to understand why.

There is a clear set of extremely-well-defined conditions required for each of these calls to work, as well as definitions of what will and will not be returned.

In the case of collections of Components, the order will NEVER be guaranteed, even if you happen to notice it is always in a particular order on your machine.

It is ALWAYS better to go The Unity Way™ and make dedicated public fields and drag in the references you want.

ALSO:

Remember the first rule of GameObject.Find():

Do not use GameObject.Find();

More information: Regarding GameObject.Find · UnityTipsRedux

More information: Why cant i find the other objects?

In general, DO NOT use Find-like or GetComponent/AddComponent-like methods unless there truly is no other way, eg, dynamic runtime discovery of arbitrary objects. These mechanisms are for extremely-advanced use ONLY.
If something is built into your scene or prefab, make a script and drag the reference(s) in. That will let you experience the highest rate of The Unity Way™ success of accessing things in your game.