What Danny said, with the caveat that some yeasts are notoriously active and are always likely to go crazy. Always best to be prepared... sounds like your improvised solution should be okay. Now that the overflow has subsided, but you have decent co2 pressure, is a great time to either replace the airlock with a clean one, or clean the dirty one, replace the fluid in it, and reinstall.
I will say, I love the 3 piece airlock, and will never go back to the S shaped. Ease of blowoff assembly, ability to clean better, and ease of topping off sanitizer are my reasons.