I'm pretty sure she'd assume you entered the main building, or just the closest one to your line of direction from the battlefield of earlier. As such, she'll probably head inside said building through the first available open doorway or crumbled wall.
"The two move southwest to the cage building (15 feet in circumference). They make a wide circle of it and see just west a square building (20 by 20 feet). Just west of that is another cage building (same size as the other). West of that is a barn."
By the sounds of it the 20x20ft square building is the most immediate. So you would like to move for the most obvious entrance?
While the most obvious entrance is not always the safest entrance, I believe in this case, it is the most approptiate for Myrrani to use.
Yes, I'm walking through the big open door that practically SCREAMS "Enter here"