«Their new measurements also show that the cloud is 11,000 light-years long and 2,500 light-years wide.» (BBC) That is a big cloud of hydrogen. A very big cloud. However, we will not live long enough to see it burst into the Milky Way. Nobody in their right mind will suggest that human civilisation will last that long (20–40 million years). If we are lucky, we can survive the next blow to our existence (a combination of overpopulation, climate trouble and ecological disaster), as long as it does not involve serious nuclear combat.
But if technology continues to develop after this crisis, somebody will at one point make a mistake (something like the virus in Resident Evil) in some state of human irrationality. So, sorry, but we will miss what according to astronomers will be an impressing firework of supernovas in the Milky Way… And if the human brain, for example due to heavy nuclear radiation, mutates into something sensible, and we survive for 20–40 million years, the exploding gas cloud (which is thousands of light-years long) will maybe turn out to be a small problem?