He shouldn't have pulled in without indicating, it's natural to tail gate a bit if they haven't signalled ahead of time. And his getting out of the car is an overreaction. But the poster should also pay attention to his lane discipline on roundabouts. Everyone makes mistakes.
The owner of this vehicle is a well-known glue sniffer. You can often find him dogging in lay-bys. His missus loves to watch boxing and sniff glue and poppers while tapping her Crap infested minge.
Why did you use the left lane to turn right on the roundabout, you basically tried to stop the Volvo exiting by being in the wrong lane.