I bought a stacked 21700 tube mech and a 25mm Goon to use with it. Because I'm not a stunt man I put a .60 ohm build in the Goon and kept it on the mod as a dedicated RDA for series voltage use. It worked well for me, pretty warm and it ramped up fast, but not volcanic and as it was a relatively tame build for series it was only 118 Watts max - probably closer to 105 ish after voltage drop, and pulling less than 14 Amps which wasn't even close to pushing my 30Ts too hard. I re-checked the resistance of the build and made sure the screws hadn't loosened before using it and every time I did a cotton change and coil clean, checked the battery wraps and condition of terminals before using the mod and after every battery charge - so as far as I could figure out nothing could go wrong. But I found a way.
I took it off my vape shelf after not using it for about 6 months, did my standard checks - all good, and started vaping. Shortly afterwards thought I should really check the switch and threads as I hadn't cleaned them them for 6 months. I stripped the mod, had a look and it seemed fine but gave them a quick clean anyway.
Re-assembled the mod and... couldn't find the RDA. Had a search and spotted it on my vape shelf. Put it on the mod - no need to check the build as I'd done it less than half an hour earlier - took a hit and burnt the crap out of my mouth.
I own 2 Goon RDAs lol and a 24mm looks pretty much like a 25 if you're not paying attention, unfortunately I'd picked up the 24 that had a 0.17 Ohm build and put that on the mod.... Miraculously the batteries didn't vent, but I burnt the crap out of my mouth and had to vape my Innokin T18 for a week because everything else was too hot. I now have a 25mm Panther RDA on the mod as I don't own 2 of them.