Ah, yes! I just did the same with a Hefe in a 6.5 gallon. I heard some funny noise in my garage and went to open my chest freezer. Right at that moment I got shot in the eye by a stream of yeast exploding from the airlock. It went everywhere. Took 40 minutes to clean up the garage and had to go in the house where the wife and kids could laugh and point. Be careful when taking out the airlock.