Valorious, I have to say, if a dog, any dog, could get my glock to fire like that, I would be more than astonished and dumbfounded. -And deaf.
Unless he had modified the trigger to lighten it up immensely, I cannot see how that'd be possible.
Not at all saying it didn't happen, I just don't see how.
I have tried and tried every way I could think of (with gun unloaded of course) to activate the trigger on my glocks JUST so that I would know the limits of the firearm I carry.
I even used to carry with a clip-draw and wanted to know EXACTLY what the real possibilities were. Tried hard as I could to operate the trigger through my pants and many other techniques. Only reason I stopped carrying that way was due to my night sights front sight catching on pants upon drawing the pistol. They were lower height sights and still had enough edge to catch a little from time to time. Just enough to be a distraction or slow you down a hair.
I've tried to hang trigger with shirt tails, strings, all kinds of unassuming things and not only is it very difficult to get the right angle to release the tiny safety on the trigger, but even if you accomplish that, you have to pull STRAIGHT back and the gun HAS to be supported enough to resist moving in that direction.
MOST AD's are from finger unconsciously BEING on the trigger in perfect position and either pulling it without realizing or thinking about it, or finger on trigger being pushed into trigger while holstering.
I'm sorry, I give you full benefit of the doubt, but I just can't figure out how that could happen.
And on top of ALL that, I can't imagine laying my loaded and ready to fire gun on a coffee table exposed to God and all creation. Even if it DID have a manual safety.