What's with this writing that changes when I press the button?

Hint 1 of 5:

Does the writing change every time?

Hint 2 of 5:

When does the writing not change?

Hint 3 of 5:

Does this room remind you of anything?

Hint 4 of 5:

Been in any small rooms with buttons before?

Hint 5 of 5:

It's an elevator!