Combination lock

It was a simple, 4-digit combination she had been using regularly, two, three times a day. In fact, just a few hours earlier that same morning she wound the stupid doll in under a minute, proud of herself that she could do it without Feyg noticing anything. "Mommy, Mommy, what's wrong with Julie? Is she going to die?" Feyg was wailing now, picking up a powerless arm of her robotic sibling and letting it drop back down onto Lidia's knee. "Mommy, Mommy," sobbed Feyg staring at the face that just a minute ago had that dear silly, confused look, and now was completely unrecognizable, skin pulled tightly around the rigid plastic bone structure underneath, without a single wrinkle of expression; a face of a lifeless doll that Julie was. Lidia herself did not have the stamina to look at that face and kept her eyes firmly planted on the girl's belly button, right hand typing and retyping the numbers into the back of the body, left arm reaching out to Feyg. "Look at me, dear, look at me," she begged her eldest daughter, and catching the glance of the tearful pale blue eyes, promised: "Everything is going to be alright. Julie has a little fainting spell, that's all. She'll be alright in a moment, you'll see!" But what is the damned combination? What is it? Another minute of this, and Feyg is going to know that something is dreadfully wrong, she will take Julie for dead, and will look at her with endless suspicion if she suddenly comes to life just like that. She will know that something is off, different, and will then inevitably discover the control pad on her sister's back, her true doll nature. What am I going to do? "Feyg, do you remember when we celebrated your sister's birthday? Do you remember when it was? What date?" Lidia made a desperate attempt. "Aaaa!" cried the girl. She didn't even hear the question. The sobs were violently shaking her shoulders. Her head fell on her chest. With only one arm unoccupied by Julie, Lidia barely managed to catch her eldest daughter when she fainted.