I take it this was -2 degrees F. Since -2 C probably wouldn't be such a problem. I've never ridden long distances at that temperature. But I think with that problem you would be better off with one of those neoprene masks with the mouth and nose cut out. Your headgear should be such that you should rarely have to mess with it. Or at least no more than once every ten miles or so. IF you constantly have to adjust it you need another approach. Try using a fitted face mask and using a neck gator. Keeping the neck really warm will help keep your whole head warm. Use the balaclava for more moderate conditions.

My guess is that the helmet moves around a bit and pulled the balaclava around. If you using a dedicated cycling balaclava it should fit kind of tight and it should stay put. A loose fitting one will have problems. Cycling ones are not as warm but are more useful. You can use other things with them when it's really cold to help stay warm. Gore-tex helmet cover blocks out the cold wind and traps warm air. A fleece neck gator as mention previously combined with the cycling balaclava and helmet cover should work for -2. And will breath much better than a standard type. Also it won't freeze up so much. The fleece neck gator is low enough that it won't freeze up.