Sounds to me like she was enjoying herself and didn't want to go in. I wouldn't worry about it. BUT what I would worry about is HOW you call her to come. Come should ALWAYS be positive. NEVER mean or mad. Never. Ever. NEVER. Got it? Never! This could be the beginning of a new routine for her now that she realizes she's got your attention for doing it.

Rules of come:
1) Make it fun. Make it a great experience where the dog is rewarded for coming.
2) Always reward the dog. The reward can be play, praise, food, toys... whatever motivates your dog.
3) NEVER call them to come for something they don't want to do (in your case, coming into the house.) Go GET HER, and take her to where you want her to go if she doesn't want to go. If she knows its something she won't like, she won't come. You've already figured that one out because you stated she never comes when called unless she thinks she's in trouble, then she lays down in a VERY submissive position. Thats not good.
4) Use another word if she's not coming on the word come. My dog comes for a ton of words.... "cookie" "nap?" "where's your bone?" "look what I have!" "you want this?" The sound of a cat food can opening. The shake of the treat bag. Anything that makes your dog come to you can be used to your advantage. Just use it in positive times so that she'll come to you no matter what, no matter when.
5) Go get them if its something they think is punishment. Punishment ot my dog is a nail trim or getting into the car. I get her and take her to wherever I need her. She'd never come to me if every time she came, I did something she hates.
6) Keep it positive! FUN! PLAY! (I know this is rule #1, but its most important )