Don't think you are safer closer to the ground. You can hit just as hard from fifty feet as from a thousand. You are never in freefall no matter what happens. There is always some drag from the worst of canopy problems. In fact you can hit very hard by swinging into the ground from very low altitude.
Height is safety.
If I'm flying in rough air I will usually fly well above five hundred feet, as that gives me at least a few hundred feet to recover, with at least a few hundred feet to deploy the reserve if I can't sort it out. If you have a big collapse, it is probably best not to just let go of the throttle as this will increase any surge due to the collapse. I keep the throttle setting the same or ease it off slowly. One other thing to remember is that collapses are more likely when you are on idle or have the motor turned off. So when you are descending to land in turbulent conditions try to keep some brake on to decrease the likelihood of a collapse.