Looks like there's a problem with the wire. Lock the cylinder in a pipe vise. If a pipe vise isn't available, try to put it in a vise so that you can lock it down tight and not damage the tube. You need to turn the cap. You might break the wire, but you can get another one. Stick something like a small pick down there and coax the wire out as you turn the cap. It may be a pain, but it will come out. It's a little difficult to tell, but you may have to turn the cap and break off the piece sticking out.
Good luck
Andy