Looking forward to this. 
But mind: Ryansoh3 really tried very hard to make a cell/flashlight go boom and he did not succeed. And beware: quality cells have internal fuses that will interfere with your attempt! And cheap fake cells may not have the amount of energy to get the desired effect.
A friend of mine has a couple ultrafire protected cells. Maybe strip the protection circuits off of them and give that a try? One charged one dead.
Trying some ultrafires would definitely be great. :partying_face:
Have you looked at your friend’s ultrafires before? There is a chance that they might not even be protected. Some ultrafires say protected on the wrapper but in reality there is no protection circuit. Just a magical protection wrapper! You can usually see without removing the wrap. And if they are protected, I’d suggest trying some experiments with them before removing the protection. I suspect some of those junk protection chips are not very good. It would be great to see one blow with the protection intact.
If they are some of the worst UltraFires (like UltraFire BRC) then they might have very low capacity. Iirc some have tested to be under 500mAh. In that case, there might not be enough energy in them to reach thermal runaway from a dead short. You can put one of those very low capacity junk batteries in series with a higher capacity cell.