Season 2 Ep.4: When KC and Lex's fake 'Antidote' doesn't cure sister Ellie, Alice goes on the warpath. Spike is supposed to be on guard at the Mall tonight, but Alice has no difficulty knocking him unconscious before proceeding up the stairs to Lex's room. To save himself, he tells her about Tai-San's new, genuine Antidote. Tai-San is only too pleased to provide her with a dose for Ellie, but Alice takes her as a hostage anyway.
There are two problems with this. Alice has only set foot once in the Mall, only on the ground floor, and only long enough to obtain a dose of (fake) Antidote from Lex. She would have no idea where Lex's room is.
The second problem is that when climbing the stairs her legs, boots and method of climbing are identical to those of Top-Hat... from Ep.2.