My shack is on the second floor and all 7 dipole antennas are in the attic and drop through the ceiling to my shack. Not the best situation, but what I could do. I have no ground to my radio other than the 3rd wire ground on my 12 volt switching power supply. As said earlier, disconnecting everything would be the safe thing to do. I don't and never have in 36 years here and other houses. I don't have any noise problems or RFI problems in the house except for external speakers on two computers and 4 ferrite beads on each fixed both. I do have a ferrite bead coaxial isolator between the antenna switch and my rig. I operate 160M through 2m from this shack. If I had outside antennas I would run the the coax in next to the fuse box and ground to the earth ground rod.
I would say a ground to earth from the second floor is really more like a short lightning rod. If it's your time, it's your time. Uncorrelated data, there has been two homes hit by lightning in our area over the past 10 years. This is out of about 20,000 houses so it happens but the odds are pretty rare.
Be sure to listen for my beacon on 28.278.8 MHz