Your exactly right, and these girls were already in fight or flee mode before they went into the water. No one in their right mind would go in after them.
The way to get someone to release you in the water when they have you in a bear hug death grip is to pinch them hard on the underside of their upper arm.
For some reason, the drowning person will let go and upen up their arms. Quickly turn them away from you in a half spin and put your arm over their shoulder and grip their chest. Talk to them as they will flail. Keep their head above water and encourage them to kick to assist you in swimming to shore.
Preferential to try to use something as a flotation device if at all possible.
*** Disclaimer: classes taken 30 years ago and exact details might be a little fuzzy.