If the universe is filled with violent incidents then it doesn't really matter how probable life is. It will take an extreme amount of luck to manage to survive through all those events. The Fermi Paradox doesn't exclude life, just the frequency of it. You could still have plenty of alien civilizations out there, but at a frequency of one every a thousand galaxies or so because everything else gets wiped out every so often.
Even with 'one every thousand or so' (which feels like a fantastically speculative number) the law of big numbers suggests this does not, in fact, 'answer the Fermi paradox'.
FWIW my (comparably uninformed by more than one data point) money is on mitochondria.
If you take the Drake equation and start speculating on a conservative way, the one in a thousand galaxies estimation is very probable. It could be mitochondria, or it could be that the universe is still too young to be safe for life on a mass scale. We're just lucky to be one of the first.
