Factual error: When Walter removes the glass disk from Bowman's hand, he asks for a forcep, but is given a hemostat, which he uses to pull out the disk. My mother is a doctor, and when she saw this scene, she burst out laughing.
Visible crew/equipment: When the sellers get out of their vehicle, the reflection of a camera is visible when they open the doors. (00:36:05)
Answer: He helped his father evade capture, impeding the investigation.