Tom, that is good news.

That was also an effective use of the ol' "shovel-cam"!

(Without seeing any pics), I think I would still recommend re-attaching that 20' section of pipe.

Your 12" overflow will move significantly more water in siphon mode. Siphons are much happier to whatever degree you can get the outlet end of the pipe to a lower elevation.

After you are out of the emergency window, you might consider installing an "anti-seep collar" when you dig out around the pipe to make your repair. If you get another problem in the future, the collar makes it more difficult for the water to create an easy path to cut out the back side of your dam.