Last minute nerves? I guess it's scary to suicide a whole country, no matter how decayed a person's heart.
As Luke says of Vader, "I know there is still good in him".
Perhaps May is in the process of remembering her own abuse as a child and will throw the Emperor (The British Royal Family) to its doom, down the ventilation chasm of the Death Star.
I think the May-requested-drawing-out is the scene where The Emperor fires relentless electricity at Luke. At this point, Vader begins to look like he's a-bit-unsure-of-the-whole-thing-now.
The idea of killing the whole country probably seemed 'a fresh new start', 'liberating' and 'larksome' during the whiteboard-brainstorms at Downing Street. But enacting destruction on this scale can often seem less appealing when the lightning bolts really start flowing and there's the smell of burning flesh in the air.
Vader didn't have the stomach for this brand of mindless violence in the end. Perhaps May doesn't either.
What do you feel?
RE: Brexit as suicide: The psychology of self-harm