So I went ahead and opened the door for her, figuring the squirrel would dash off as soon as it heard the door, but it didn't seem to notice it at all. That was so much the better for Miss Oribel's plan!
She hightailed it out there, so fast and single-minded that she didn't even notice that the deck now had 3+" of snow on it that it hadn't had three or four hours earlier!
She was less than impressed when she realized what she had gotten herself into. She stayed out there for a bit, did a bit of a "see if I can dig myself a clear path back" routine, decided to hunker down for a while when she realized that she really was going to have to walk back through all that snow. It did start snowing again and she decided it would be best to come back inside and get a few kitty treats. (Probably a good thing she doesn't know about hot chocolate with whipped cream on a cold afternoon!)
I'll leave you with one more picture of her, just because I am not sure which one has the best perspective of her leaping tracks in the snow (though, as always, they will bigify if you click on them).