The character is behaving this way because he wants the money and diamond dust all to himself. Whats going through pup's mind is how quick he needs to be before the cops come.
Pup is behaving this way because he eagerly wants to escape the cops with his valuables. What's going through pup's mind is how fast he needs to go in order to escape the cops with what he stole.
Pup was behaving terribly as the cop tried to get him. He eagerly wanted to get away and wanted to shine bright. Whats going through pup's mind is how much he failed his mission and how much he did and how much it wasn't worth it.