Either scenario is possible. But if your second one is 'probable', then why has nobody else in the Universe done it already? If they had, surely we'd see evidence? I really can't believe we are the first to get to this stage, we've only been here for the last few thousand years of a 4.5 billion year old planet.Can't agree with your use of the word 'probably', seeing as there is absolutely no evidence of that happening so far. I'll give you 'possibly', at a push.
There is always a 'possibility' that AI will create some kind of unstoppable malevolence, or that messing around with quantum particles will create some kind of anti-matter that will consume the entire universe. Or maybe bashing hadrons together at close to light speed will create a black hole on earth. It could all be possible of course, but 'probable', no. The fact we're so aware of the potential risks with emerging technologies suggests that we aren't going to allow them destroy us.
I would say it's more probable, given current trends, that our technological advances will continue exponentially, as they have been. We will advance to free and limitless energy - knowledge and information, and with it technology, will continue to progress so rapidly that we will eventually become like gods, no longer bound by physical limitations. Space travel will become effortless. Natural disasters, pandemics, comets - none of it will be able to touch us, as we learn to control the physics of the universe and the biology of ourselves, as we ultimately colonise the solar system and the galaxy.
I'd argue that there IS evidence of it happening so far. Or at least more evidence for my scenario than yours- the evidence being that there doesn't seem to be anybody else alive out there.
Like with the Jao Pedro situation, I would much prefer to be wrong on this than right though.