I'm thinking more of the sloppiness beforehand. Millard is 6'4 or something and already stands out before the man purse, tattoos and use of his middle name. That stuff would all have likely been okay if police were only investigating a truck theft, even an audacious one. But murder? There's risk taking and then there's a wildly inadequate sense of self preservation. The cell phone evidence is important to this point I think. They clearly demonstrate an awareness of not leaving a trail - the burner phone was shut off immediately after it's last use, for example, and Tim's is shut off presumably right after his death. But their personal phones were carted to a planned murder? And MS decides to switch his off only after they commit the murder? That doesn't make a lot of sense to me. What makes more sense to me is not knowing they were going to be killers, and then each of them having a different reaction. Smich to turn his off, Millard maybe deciding that in a bad situation with no good options he is better to leave the phone on and at least be able to have a half-assed argument of no cognizance of guilt. The sloppiness after was probably mostly little planning, inexperience, a little bad luck and running out of time.