Sorry to hear about the whoopsy and your further pain Pete, hope you get well soon.
i have had similar experiences with kite/buggy releases over the last 20 years, so I refuse to hot wire to the buggy at all.
i have an aircraft seatbelt buckle on my buggy, and I have carried a rescue blade/cutter on me at all times since I added a belt to my buggy.
i have used the cutter a couple of times, luckily not in a life threatening situation, but it is definitely a permanent part of my kit.
cheers, Dukey