If it has some sort of speaker protection relay then you should be fine. If is functional there should be a detection circuit that will open them and ground out the signal path if something happens.

if you are worried about your ears, use ear plugs until you are comfortable

I personally have not seen this occurrence in 45 years.

Your ears will be fine.

Some (rare) catastrophic fail might occur which will destroy all/part of the output transistors and blow both tweeters and if awesome enough fry the mids…the woofs should be ok… maybe.

A long running joke is…the tweeters gave their life so the protection circuit/relay could live. 😬

I regularly use solid state amps that are over 30 years old. I just sent one in for service because of an oscillating distortion and flashing power light in one channel. No damage whatsoever to the speaker and no flames shooting out of the amp.

I had a cap blow in an old monitor and short out, and **** me it was a loud bang.

The worst case scenario ends with you in your underwear standing out in the snow on your lawn watching your house burn down while your wonder if the ringing in your ears will ever go away, and then an asteroid strikes and takes you out of your misery. Fortunately worse case scenarios virtually never happen. So, if I were you I wouldn’t sweat it. ;)

Tube amps can have some pretty spectacular failures, but weren’t the Futterman OTL transistor amps basically ticking time bombs for crowbar’ing an ridiculous voltage to the speakers?