That has everything to do with leaning before/during unclipping. We've talked about this before (where is the thread)???

The sequence is, first turn the handlebars slightly AWAY from the direction you plan to unclip (e.g., if you unclip right, turn your handlebars slightly left). Turning the bars left induces a right handed lean, so your bike will begin to fall to the right. As the bike leans over, unclip the foot, so your foot is ready when it's time for it to hit the ground. As your toe hits the pavement, stand up off the saddle so you can support your weight.

If you're falling to the wrong side, pay closer attention to which way you're leaning before you unclip.