I spent some time yesterday morning reading the discussions around managing an overfire situation, and honestly thought it would never be a concern with my recently rebuilt Firelight 12 due to the ability to really close down the air supply, and the further restriction the cat provides when engaged. That position hasn't changed, but what I never took into consideration is how to manage the fire if the glass breaks during a burn. During my rebuild, the pane on the right side was broken, but the left looked intact. I therefore only chose to replace one. My assumption was that it was the correct type of glass, and that once cleaned and regasketted I could use it as is. Not sure it it was tempered instead of ceramic, tightened too much when put back in, or just fatigued from a long hard life, but it cracked wide open during my first attempt at a larger load of wood. Temps were by no means unrealistic per the multiple thermometers I have mounted, I never left the stove unattended so I could observe the burn behavior, and no wood ever came in direct contact with the glass. I remember sitting there watching Moonshiners as the fire was just starting to get going, when I heard a snapping sound in the direction of the stove. Didn't think too much of it since all looked fine, but then I started to hear the stove pipe ping and pop, and the fire was looking far more vigorous than it did a short time before. Temps started to climb on both the flue and the stovetop gauges, and despite closing the air supply all the way the fire kept getting more intense. I checked all possible air supplies (open doors, not completely sealed top loader, the condition of the air control lever, and all looked fine. Panic was starting to set in when I looked at the stove from a different angle and noticed a crack that crossed the entire pane of old glass, but was obscured by some of the decorative iron on the door. Upon discovering my uncontrolable air source and realizing I hadn't thought of anyway to mitigate that type of failure, I thought back to the reading from yesterday and grabbed the partially filled ash bucket from upstairs. I then engaged the catalyst chamber to reduce the draft and watched intently to see if I'd have to pour the ash bucket down through the top loading door to prevent a meltdown. Thankfully the temps slowly started dropping, and after a couple hours of babysitting I finally felt safe to go to bed. The glass crack had opened more, but the reduction in draft was able to bring things into a manageable state. Going forward I'm going to implement my favorite idea from the group which is to fill a bunch of small plastic bags with sand to be used in emergency cases like this. Sorry for the length, but thought I'd share a failure mode I never planned on having to address.