This isn’t anything critical, I’m just curious:
if the length of the level1Passwords array is 6 (there are 6 items in the array), wouldn’t the random generator read
Random.Range(0, level1Passwords.Length)
as
Random.Range(0, 6)
?
How does it automatically know to go 0-5, not 0-6? Am I misunderstanding .Length, or is there some funny business going on under the hood?
This is an interesting one. I added the following PlayMode test to Hacker.cs to show that the code works as is:
[UnityTest]
public IEnumerator TestRandomRangeArrayNotOutOfBounds() {
int numIterations = 1000;
Debug.Log("Level 1 Passwords Length:" + level1Passwords.Length);
Debug.Log("Test runs: " + numIterations);
int[] results = {0, 0, 0, 0, 0, 0, 0};
for (int i = 0; i < numIterations; i++) {
int randResult = Random.Range(0, level1Passwords.Length);
Assert.AreNotEqual(randResult, level1Passwords.Length);
results[randResult]++;
}
Debug.Log("Results: " + String.Join(",", results.Select(x => x.ToString()).ToArray()));
yield return null;
}
Which returns as follows in the TestRunner:
Level 1 Passwords Length:6
Test runs: 1000
Results: 179,168,178,168,139,168,0
So you can see that 6 is never returned from Random.Range(0, level1Passwords.Length) even though the Length is 6.
Now I thought this was curious, as the API docs state that the min and max of Random.Range are inclusive, so the result should be 0…6.
Returns a random float number between and min [inclusive] and max [inclusive] (Read Only).
HOWEVER 
If you scroll further down the page, you can see that Random.Range is overloaded for ints, and when you use ints instead of floats, the max is exclusive:
Returns a random integer number between min [inclusive] and max [exclusive] (Read Only).
Mystery solved
Ahhhh, I see. Good detective work. Thank you!