In the early hours, Ellie was caught red-handed trying to strangle Ebony in her bed at the Hotel. The Technos raid the Mall at dawn, and force Lex to tell them where Ellie's room is. And we see her computer, the one she used to create The Amulet Newssheet being taken away.
And the Goof: Ellie's room is downstairs. You can see it! The one that has an arched sign above the door that reads "THE AMULET". That's where she has the computer - the orange iMac. There's no way it would have been upstairs.