While Alex, Piper, and Mia are waiting for Jo at the hospital lobby... Mia is sitting next to Piper on the right. The next shot Mia is sitting next to Piper on the left.
After the car accident Benny has blood on his head from where his head hit the steering wheel, when he gets to Jo's house the blood has nearly disappeared. The head injury is also never mentioned.
During the chase scene Benny's arm goes between hanging uselessly because of his injury and swinging easily.
Any collision severe enough to do that much damage to the vehicles, and stop them both at the point of impact would have activated the airbags, but there is no evidence of it happening.
When Benny is reciting the license plate he clearly says REZ but When Jo and Piper repeat it they both say RDZ which is also the title of the episode so that is the correct one.