Why is my baby like a T-rex?

Remember in the movie "Jurassic Park" one of the dinosaur experts was saying how the T-Rex has extremely poor vision and that as long as you don't move or make a sound he cant see you? Well Lucy is pretty much the same way in the nighttime.
I STILL habitually check to make sure Lucy is breathing before I go to bed at night. Last night I went in to check on her as usual and discovered she had removed the lower half of her jammies. I am sure for most toddlers this is not a big deal, but for Lucy, it simply meant that by the time she woke up in the morning she would have stripped naked- leaving me with an extremely disgusting set of sheets by morning once nature takes its course.
I stood in the dark, debating whether it would be worth it to awaken her to put her jammies back on. Sure enough, while I stood in the dark trying to make my decision, that little stinker opened her eyes and looked right at me. I froze, my hands directly over her (I had been reaching for the jammies) and she blinked several times. I remembered the advice of Dr Grant from the movie and just stood VERY very still. Sure enough, she didn't see me and went back to sleep. Whew.
At that stage, I gave up and decided I would have to deal with the risk that she would take off her diaper in the morning before I could get her.