I would toss the pack. I had a Maxamps pack (2s 6000 mAH) do the same thing to me and it just got worse. A few runs after I noticed it was puffing it was puffed enough to put strain on the battery hold-down in my Rustler. I figured after a while it wouldn't be able to handle it anymore and would do something a little more spectacular so I stopped using it.
With that dead pack I took the shrinkwrap off and threw it at the ground as hard as I could. All the cells flew apart in different directions and bent pretty badly but no massive explosion or anything like what you see on YouTube. My 2nd Maxamps pack that went bad was a 3s 6000, and it got a much more deserving end. All that happened to that pack was a whole lot of smoke.
I love sharing those pics, good carnage
If that wasn't enough to get flame, I doubt they are really all that volatile. My 3rd and 4th Maxamps packs died a less spectacular death, they just got worse and worse at staying balanced and wouldn't take a full charge so I sent them back. 5th and 6th packs are still going, they will probably get the same treatment when they kick the bucket.
Bottom line, toss the pack. Good lipos are getting cheaper and cheaper all the time, it's not worth the risk IMO.