There are five bullet wounds of entry on the right side of the back: three on the posterior chest cage and two over the right lower posterior lumbar areas. From up downwards:
 The first is located in the 5th intercostal space, 3 and 3/4 inches right of the midline.
 The second is in the 8th intercostal space, 5 and 1/2 inches from the midline.
 The third is in the 9th intercostal space, 1 and 1/2 inches from the midline.
 The fourth in the tip of the right 12th rib, 3 and 1/2 inches from the midline.
 The fifth is over the crest of the posterior right iliac bone and 5 and 1/2 inches from the midline.
There are three exit wounds:
 The first is over the left interior chest laterally and left margin of the breast, in the 4th intercostal space and 5 and 1/2 inches from the sternum.
 The second is in the anterior abdominal wall, below the xyphoid process and 1/2 an inch from the midline.
 The third is laterally and 3 and 3/4 inches to the right of the umbilicus.
Heart: A bullet wound penetrates from right to left through both atrium.
Lungs: There are three through and through bullet wounds, corresponding to the three bullet wounds of entry on the right posterior chest cage and one bullet wound through the left lung, in line with the wound through the heart. They are associated with extensive hemorrhage of both lungs.
Abdominal Cavity: A bullet wound penetrates the liver. A bullet wound penetrates the right kidney, the left is normal.
Head: No injuries or skull fractures.
The bullet wound over the posterior iliac crest penetrates the deep muscles and exits to the right of the umbilicus. One bullet is recovered in the subcutaneous tissue of the base of the anterior neck (left side) and the other bullet in the subcutaneous tissue anterior to the right 7th rib, which it penetrated of the sternum. The entry wounds aperture 3/16 inch in diameter. The exit wounds are larger.
One can see that four of the bullets that exited or remained in the body, are all situated to the left of the entry wounds, the fifth bullet traveled from right to left also. Bullets do not necessarily follow a linear trajectory when they enter the body, they can be deflected by the body's structures, but here the pattern of all five bullets show a distinct right to left trajectory. The chances that all five bullets deflected to the left from a shooter standing directly behind Betty Lou Jensen is slim, indicating her body position was oriented on her right side in relation to the shooter for many, if not all.
'The bullet wound over the posterior iliac crest penetrates the deep muscles and exits to the right of the umbilicus'. This is bullet , which literally enters and exits her body one and a half inches offline. It entered her lower back (dark mark) and exited the front of her body '3 and 3/4 inches to the right of the umbilicus', indicating she was likely running away from the shooter at this point, in an upright position.
Every bullet that entered Betty Lou Jensen traveled from right to left.
Four wounds, marked in red (2 exit wounds from the front of her body and 2 bullets that remained in the body) can be seen marked on the upper portion of Betty Lou Jensen's back, yet two bullets entered low down on her right side. We know the trajectory of bullet , so bullet  clearly traveled from her lower back to upper back, strongly indicating that Betty Lou Jensen was likely hunched over at this point, struggling to escape the relentless onslaught. The likelihood therefore is that bullets ,  and  effectively traveled directly across from the right shoulder area to the mid and left side, as stated here; 'Lungs: There are three through and through bullet wounds, corresponding to the three bullet wounds of entry on the right posterior chest cage and one bullet wound through the left lung, in line with the wound through the heart. They are associated with extensive hemorrhage of both lungs.'
It is difficult to ascertain the exact order of the wounds inflicted that night, but if the uppermost hole in Betty Lou Jensen's dress contained the gunshot residue, then it could be argued that bullet hole  was the first shot fired, and likely bullet hole  may have been the fatal or final shot that night, as the autopsy stated 'Heart: A bullet wound penetrates from right to left through both atrium.' The trajectory of bullet wound  is consistent with injury to the heart.
The following diagram illustrates one possibility of the order of events that night.
It states 'Pellet found in pants of victim Betty Lou Jensen, at mortuary, during examination of the deceased. The pellet had entered the lower back, coursed through her body, emerging under the waist band elastic of her panties, where it was found.'
This bullet was also described in the police report; 'Pellet recovered near victim Betty Lou Jensen in blood spattered path on her attempted escape route. Pellet entered her body in the back and emerged from the center of her stomach and dropped to the ground without penetrating the front of her dress.' The stomach is situated beneath the heart, so was likely not the fatal shot that night.
The police report stated it was found along her escape route, not necessarily where she was finally discovered. Betty Lou Jensen likely staggered a few more feet, twisting to her right side, possibly falling to her knees. The final shot was likely bullet , striking 'the 9th intercostal space, 1 and 1/2 inches from the midline', traveling 'right to left through both atrium.'
Now angled to her right side as the final deadly shot is delivered, she falls to her right side, as viewed by Stella Medeiros. The woman who spotted the stricken couple as she passed the turnout stated "The girl was lying on her right side facing the road." Betty Lou Jensen would finally collapse onto her front side, her body aligned on the east/west axis to the rear of the Rambler.
The image below shows the order the wounds may have been inflicted (white numbers). The further Betty Lou travels away from Zodiac, the narrower the angle tends to become in the bullet path. Depicted by the green arrows, bullet paths 1 and 2 are quite extreme, whereas bullet paths 3 and 4 have narrowed between the entrance and exit wounds, to 1 3/4 inches and 3 inches from right to left. Please remember the red circles are either showing the exit wounds (E) on Betty Lou Jensen's front side, or the bullets resting positions within the body. Bullet path 5 could possibly be determined by Betty Lou Jensen having collapsed on to the turnout floor, her right side facing Zodiac, when the final shot is discharged, ending her flight for freedom.
This analysis requires heavily on little bullet deviation from the internal structures of the body, nevertheless it attempts to give a rudimentary explanation of the right to left trajectory of all five bullets that night, that was unlikely to have happened just by chance.