Definitely try to avoid being in that situation, but sometimes it's not up to you. The trucks are faster and may catch and pass you when you didn't expect, then make a quick right turn in front of you. A mirror may help, though not always.
So you're saying that after the cyclist enters the intersection, a truck comes up on the left, passes, then turns right in front of the cyclist and runs him/her over?
I agree in that situation there's pretty much nothing the cyclist could do. In real life the cyclist can see if there's a truck on their left as they approach the intersection and either speed up to get ahead of the truck or slow down to avoid the potential right hook as @
FBinNY has already explained.