So I know this is very bad news. I've unplugged the fuel injector to keep it from dumping gas into a cylinder that doesn't fire. My question is can I drive this safely in this condition and if so for how long? Any major contraindication to driving it on the remaining 5 cylinders? The rest of them have good compression.

 

Some engines (older and recent) are designed to change the number of cylinders that are working.

How does your engine run now?

Given your engine is designed to run on 6, running on 5 may cause the engine to idle poorly, vibrate, check light come on which could cause the computer go into some kind of safe mode, lower MPG. If the fuel is cut off, the engine itself may be OK over time.

Another issue is why is one cylinder low. Bad head gasket which may bet worse?