Is it dangerous if your tooth is danglingly around and it is lose, and is ready to take the root and everything else?

Could be. If the tooth is loose, you need an xray to determine if it is broken or periodontally involved. In either case you should schedule a dental visit as you may swallow it, or worse yet aspirate it requiring lung surgery to correct the problem.
Potentially. If the tooth came out while you were sleeping, you could aspirate it (inhale it) and choke on it. It is best to see your dentist and get this tooth removed.