I need some advice ASAP!

Here is the situation:

I am doing a complete suspension overhaul on my 72 diesel. I have succesfully replaced the front shocks, and am working on the rear now. Since the back end was sagging considerably, I opted for a new set of springs and shocks for the rear.

I borrowed a Klaan style disc compressor from a Mercedes shop. The discs were not the correct size for the spring, but I stupidly used it anyway. I removed the right spring and reinstalled the new spring with little difficulty.

On the other side, however, I experienced a problem. During removal of the second spring, one of the plates slipped and the spring popped back into the control arm on both sides. I was scared ****less, and returned the compressor to the garage.

Today I bought one of these:



I used it to remove the spring with no problems. I unscrewed it, and began to compress the next spring for installation. I got it all the way tight, when the hooks slipped. Now, the hooks seem to be barely gripping the coils on one side of the spring. The spring is almost fully compressed, but bulging from one side. One side of the spring is more compressed than the other, and the compressor rod is not going down the center of the spring anymore.

I am once again very, very scared to touch the spring, because I dont know if it might pop out of the compressor. I swear I heard a couple slight popping noises coming from it, as I sat on the other side of the garage pondering. I think it might slowly be working itself free.

The spring is sitting compressed between a couple tires, inside my garage, with cars on two sides.

My questions:

If it breaks free, what is going to happen? Should I be worried about parts flying through walls and injuring people in neighboring buildings?

What is a safe way to decompress it, assuming it doesnt work its way free overnight?

Any tips and advice greatly appreciated.