As has been said - There but the grace of God etc.
I have had two similar incidents and fortunately got away with both without any damage.
The first was in London. I was driving a motorcycle and waiting to turn right onto a main road. Along comes a Police Car indicating left into my road ( thought). Well I pulled out and just missed him as he went straight on.
He gave me a dirty look as if it was my fault, my look was even dirtier I can tell you.
The second was more recently. I was again waiting to turn left out of my local road onto a country lane. A bus was approaching and suddenly indicated left and slowed down. So I pulled out across his path and he braked hard and blew his horn, I accelerated and missed him.
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He was going straight on and was indicating to pull up at a bus-stop fifty yards beyond the turning. In my defence I would say that 80% of traffic on that road turn left into this road, but I always wait till they slow down before I pull out.