All I can think about is any life that was (emphasis on past tense) on that "side" of the galaxy when the gravitational wave that dislodged 3C 186 whipped through. It's all gone now right? Seems we are pretty lucky to have this rock stay in more or less the same place, unperturbed by galactic events, for 4.5 billion years. Doesn't matter if you're a multiplantary species if a gravitational wave strong enough to move a supermassive blackhole comes through.