When you see the sight that greets her, you can understand why.
Carlos has fluffed his feathers up and looks quite a fearsome bird. As well as having his wings outstretched, his head feathers look as though they are standing on end. Overall, he looks most impressive!
The female's part in this process appears to be quite simple. "Lie back and think of England" comes to mind!
The couple have rotated slightly as a result of Carlos's activity. It doesn't look as though this has anything to do with Megan.
Less than 2 seconds have elapsed since Carlos came into the box.
A second later and its all over. Here you see Megan disappearing out of the box.
Carlos hops up to see where she is.
Presumably reassured, he drops down to the floor of the nest box again to recover.