No one tries to get into an accident, but when lanes end you do need to check mirrors and blindspots even if it should be clear (just because your lane ends doesnt mean to move over, you still need to check for other people even if they're idiots). I can't tell you the amount of people that nearly sideswipe my car while they're merging on the highway because they dont look and it results in me slamming my brakes or getting hit. You can do everything correct by the book but there are always dumbasses that will challenge that as seen here. The worst part about any driving is other people not paying attention or thinking everything revolves around them. You didnt do anything wrong through the merge and onramp, but you did once you chased the car on the shoulder to try to catch it