First, she looked back to make sure that the no one was looking.
Anne Lawson saw her, but kept quiet.
Then she decides Wells needs a bit of a distraction, so she tickles his toes, while looking back at the camera as to say "what, I am not doing anything".
Anne Lawson keeps a close eye on Sadie, yet is too busy drinking her milk to warn her brother.
Finally, she goes in for the kill and gets the sippy cup!! Ahh, the power of flirtation!