1997 Chevy Cavalier broken spark plug

Hello, I was changing my plugs in my 97 Cavalier and one of the plugs #3 broke off at the nut on the plug. The rest of the plug still remains in hole. Its really stuck in there badly. Is there a certain tool to fix this problem?

I guess my question is--can I run the car on 3 plugs with the 4th plug missing entirely? Would oil go everywhere or what? I just need to get it down the road a few miles to mechanic but am afraid to try and am scared to turn car on with 1 plug missing? Will it cause fire, etc. I tried to put the old plug back in to fill the hole, but since it broke off at the nut, it just kind of sits there freely. Whats your take on this? Can I run on 3 cyl with 1 hole completly exposed and what could would happen? Thanks! Mike