Errr, can you not see that the car has come from the left lane (as we look at it), and is crossing into the other lane because the on-ramp ends abruptly?
DW makes a small swerve to avoid the car - and maybe he thought he was clear of it as he tries to regain his same position before being hit...
OK. Stills and video clearly show him riding in the centre of the lane, without deviating, and the car coming over into his lane as it enters the roundabout.
The car was behind him and should've seen him....but was probably checking the mirrors for cars, & wasn't expecting a cyclist to be on a...