I thought of a few things overnight:
1. Is it possible that Juan DELIBERATELY tried to bait Jodi when Juan talked on and on about how the family was tormented to know whether Travis was conscious and aware when Jodi started cutting his head off? It seemed to me that Juan went on for a very long time on that one point. Could it be that the criminologists thought that might provoke Jodi to speak out to aim to hurt the Alexander siblings even more?
2. I never realized this. You know how Jodi took ALL those pics' of Travis, in bed, in the shower, b4 murdering him? Well, Jodi is such an immature Narcissist, don't you think that in Jodi's mind, she was committing the perfect murder - see, there is nothing that Jodi loves better than to have HER picture taken, to be on camera, so in her twisted and immature brain, she felt she would be getting Travis elated with the 'high' of having pictures of him taken, only to pull the trick suddenly and shoot him in the head !!!
I am also thinking that what Jodi did was had Travis in that 'last' sit-down pose in the shower, and Jodi 'steps out' for sec', tricking Travis about something or other, and then Jodi returns with the gun. Travis is shot into his upper right forehead and the bullet made its way to his cheekbone on the other side of his face, and did not wreck Travis' brain much. So, the reason for that bullet angle would be that, as quick as he could (all wet in the shower), Travis twisted to the right and put his right arm on the floor of the shower to help himself get up fast, but ...boom....