In an emergency, and if you don't happen to have the gift of foresight to carry a nice piece of rope for getting your arm out of a #330, you can substitute a strong bootlace, length of wire, or even use a snare cable. Use your feet and pull upward in an emergency situation, if possible. This way you still have a free hand to put the safety catches on with.
An old-timer taught me early-on never to stake a #330 or wire it off until the set was finished. Otherwise you may not only have to deal with getting your arm out of the #330 but also getting the attachment undone so that you have enough room to work the springs back open.
He used dog leash snaps on the end of his #330 chains so he could unsnap them with one hand.
He also had a spring compression tool he made from a caulking gun. He cut the caulking tube support off so that all that was left was the plunger, ratcheting handle, etc. He bent the end of the ratchet rod on the end so that it could hook onto one spring eye. Then he had an "S" hook attached to the casing near the top of the handle, and the other spring eye was hooked in this. By squeezing the ratchet handle, you could compress a spring literally with one free hand. The ratchet would also then "lock" in the spring in this compressed state so you could replace the safety hook with that same free hand. Release the spring tension by simply twisting the ratchet rod on the caulking gun. I think a lot about his little tool he made, and bet this would be a slick setting tool just as much as it was a safety tool.
Jim-NE