Just a couple of near misses and stupid failures I've had in my release mechanism so no one else does the same.
My own stupid fault before you point it out.
1. Putting the ice cubes in plastic bags instead of net bags. They melt and stay put with a bag full of water, even small holes can seal up and stop them dropping. A close call, I had to escape another way.
2. Release using weak string. I snapped my secondary secape mechanism whilst trying to use my primary eascape mechaism due to the string being too weak. Use paracord. Don't rely on normal string.
3. Test your escape mechanism, I used a secondary which was a frozen bottle of water. I didn't need it in the end, but found it still melting a day later. If I had needed it I would have been F####d.
4. Plan for power failure. If you use ice, plan for the power to go out as well. I have never had it, but wouldn't stage my life on it. I now use salt in my release ice. It will melt even after your heating turns off.
Your life is precious. Don't take chances, think it through and plan for failures.
I thought everything through and still the above failures happened. Think it through to the N'th degree!