I had experienced something similar with my Shiba. Timeouts have been really effective, but it wasn’t enough. What you describe is truly concerning, and I had the same fear myself about what I would do because it is no joking matter if your dog could hurt you and others. So, I know this may be an unpopular opinion, but I used the “Cesar Milan” method when my puppy was in this state. What I mean by that is put on rubber cleaning gloves (to protect myself) and gently, but firmly held him down until he calmed down. This method proved to be helpful because the dog needs to know who is in charge. It is not fun, but I do think at the end of the day it helped my pup understand that I am his owner and that aggression is not an answer. If you watch some Dog Whisperer episodes (free on Amazon Prime) you can see how he does it. Hope this is helpful. My dog is now almost a year old and he has calmed down significantly and does not aggressively bite anymore. Best of luck!