Well, sounds like you killed the cell, but the solder joint may have come off. Usually it takes quite a bit to get the cells apart, so it is probably a dead cell. If you want send it to me and I will take it apart and let you know what is wrong. Check my sig for more lipo info if you like.
I believe some Lipo's have a "fuse" inside them. Rather than exploding in a ball of fire in a dead short situation, this weaker conductive run will blow.
I shorted a 5000mah 2S pack one time with the same result. It pushes ALOT of power before it lets go though.