There are three persons...first, second, and third.

First is when the narrator is the main character and tells the story for himself. "I did this and that."

Second is when the reader is the main character and there is an actual or implied "you." This is usually reserved for the imperative. Instruction manuals and cookbooks, for example. You may also remember the "Choose Your Own Adventure" stories, though.

Third person is when the narrator is removed from the story in some way and tells it for the characters. He/she/they/it.

Now, when you choose third person, it gets interesting. How much does your narrator know? Where are his eyes? What does he see/sense?

An omniscient narrator knows all, sees all. This is becoming less popular but can still make for an interesting story when well done. You can choose what information to tell and withhold as an omniscient narrator, but the more you make it obvious that you are withholding information the more intrusive the narrator is to the story. The more it is obvious that you are reading a story rather than experiencing it.

Third person limited omniscient means that the narrator sits in one character's head and tells the story from there. This narrator has access to all the thoughts, feelings, and senses of that one character and it is considered poor form to purposefully withhold any of that if it's important. (That isn't to say you have to infodump their head on the first page.) The advantage of third person limited omniscient is that you can make it feel like the reader is experiencing the story with the character. I find these kinds of stories particularly enjoyable to read and to write. You can always use more than one viewpoint character, but you need a chapter or at least a scene break to switch viewpoints and then you have to be completely honest with the second character's point of view.

Now, who is your point of view (POV) character in third person limited omniscient? Anyone! The idea of main character and POV character are different. You can have a sidekick or an interviewer tell the story, but when you do that you have to understand that the story teller is an important character as well and that we will be deeply entrenched in their heads. We need their emotions, thoughts, and attitudes about the story.

If you want to switch POV -- and it's unconventional in a short -- I think you should mark the change with a blank line.

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Nothing pulls me out of a book worse than a mid-chapter POV change. Thomas Harris is very, very, very guilty of this in his early novels, but has stopped in his more recent books (thankfully.)

And OSC's book is excellent. Christine did a good job of summarizing it.

I like the way George R. R. Martin does it. Each chapter in a single POV and the chapter titles bearing the name of the POV character. Absolute minimum chance for confusion.

From what you described of your story, you might consider sticking with one POV or the other.