If you did somehow get an ego passthrough to blow while charging, it would blow out the bottom, away from you. I've dissected one. Once you unscrew the bottom cap, it's just a piece of plastic between the battery and open air.
IMO, this risk is getting overblown. The Li-Ion battery in your cellphone can blow next to your head. Your Li-Ion battery in your laptop can blow and burn your house down. It's just not very likely. I mean win the lottery unlikely.
I had an episode the other day. I forgot to turn my VV box mod off, and set something on top of it. Some minutes later, I reached for it to get a few vapes.... The carto was very hot. I opened it and removed the
batteries. The voltage regulator was very hot, but the batteries were cool. After the entire device cooled off, I reassembled it, and took a drag. YuuuuuuuuKKKK. The carto was trash. Pop in a new carto...good to go.
So, I'm out $1.50.
Protected batteries work.
Still, I told the wife about it, and used it as an excuse to get a Provari!!!!

There's an up side to everything.