Sounds like yet another case of, "It's only a bike, it's not moving."
I've had people pull out from the right when I've been riding along at 30mph. I overtook one once.
It was funny watching them look in all their mirrors with a puzzled look on their face, trying to work out the vanishing cyclist trick. Almost as funny as the, "How the f**k did he get there?" look on their faces when they saw said cyclist in front of them and getting away.
But, my usual trick, if the road is clear, as it often is in these situations because they don't usualy pull out if a car is around, is to ride alongside them on the outside and watch them try and see where I got to as we both trundle along at 25-30 mph. They never know what to do next.
Haven't done that for a while though. (cos I'm getting slow)