Nuns on the Run

I should be able to think of some pun for this, but I can't.

Was driving down to Sydney, looked in the rear vision and saw a couple of nuns in the car behind.
Nuns in habits are such an unusual sight that I lifted the camera and took this.
Sadly, the lights changed, so I only got one go.
Still, you get an idea of the delights of Parramatta Rd, Sydney traffic and the big truck in front of me.
After the lights turned green I checked and they were still sitting there, chatting.