Character mistake: At the hospital, Alice's husband says, "Here we are, in a major hospital, and they only have one elevator." In fact, there are two elevators, right beside each other. He actually looks at the other one before making the comment.
Suggested correction: He meant one elevator bank that actually worked. During the time they waited, none came.
Exactly. He says "they only have one elevator running", which is different than saying they only had one elevator.
Character mistake: When Alice is making the video with instructions about how to commit suicide, we see her typewritten notes, and she has misspelled "labeled", something a linguistics professor wouldn't do.
Suggested correction: Both "labeled" and "labelled" are correct spellings of the word. Labeled is chiefly the American spelling whereas labelled is chiefly the British spelling. It should be noted, co-writer Wash Westmoreland is British.
Alice was an English (American) linguistics professor. She would have correctly written the American version.
There is no "correct" American version. Both are acceptable in America.