Team Anna!
There was no place that Elsa'd rather be than right by Anna's side on this, and she was glad that Anna seemed to feel the same. Not only did she want to assure that Anna had the most protection possible on this one, she was admittedly a bit of a micromanager, (being the queen had its consequences, after all) and liked that she got to be Anna's personal guard in this one. She wanted her sister safe, and any opportunity she had to do that personally, she did.
"Just don't run off, okay?" Elsa said, knowing all too well that it was a necessary statement to make. Anna's history of running off to save the day on her own was not great, and in this situation, it wasn't something she wanted to risk. "I'd rather we all make it out of here in one piece."