Shorted Cell

[highpowerhobby]

I direct shorted a zippy 5000mah 4s pack....nice spark. There is no puffing and or fire!. Now when connected to the Hyperion is shows number 3 cell as zero volts the other cells are fully charges. There is no output voltage at the battery plug. Why is there zero volts at one cell and no volts at the output. I would think the bad cell would show something. Did a solder joint blow off?

I am nervous about taking them aprt to look...could easily short them again.

Any ideas?