If it took 5 shots with any kind of rifle, he was shooting in the wrong place. Even a 22 is enough at close range. For future reference, tell him NOT to shoot between the eyes. (I'm assuming that's what he did--it's the most common mistake.) That just hits the sinuses. To hit the brain on almost any animal, draw an X from the eyes to the ears and hit in the center of the X.

No, you would have put her in the backseat of your car and brought her home :P (And I can't deny considering that myself.)

Unless you carry a fairly large knife in your car, it's unlikely you'd have really had the option of doing that--I can't imagine trying to saw into a large animal's neck with a little pocket knife :(. I was driving the work truck, so I had my necropsy knives with me, and I carry a hunting knife in my car specifically for that reason.