I don't have direct knowledge, but I can surmise (ok, call it opinion, nay, call it a guess). You are probably OK if you had the water lock on. Yes, you were open to the air. But, it wasn't a straight path to the outside, and bacteria wouldn't have crawled through the convolutions of your dry water lock.
See Figure 4
about Louis Pasteur's experiments to settle the question of spontaneous generation.