Lyall stopped when "Sandra" turned around. She still looked the same for the most part, but it was clear that something unnatural had happened to her. She was possessed, and he assumed that it was by the very Duel Monsters spirit Sandra had put all her faith and love in earlier. What an ironic twist. Lyall had heard from Kerykeion that things like these could happen if the wielder of a powerful Duel Spirit wasn't strong enough to control it, or if the individual had struck some sort of deal with the spirit. 

The Evilswarm spellcastress descended to the floor as "Sandra" began causing electrical anomalies around her, all while walking closer to her master. She held her Caduceus staff to the side, ready to strike if commanded to. Lyall shook his head, though he did imply that she should stay on guard.

"I have something [i]you[/i] need? Funny, I was going to say the same thing to you. It'd be a good idea now for you to return to your rightful place and let Sandra have herself back, I'm not really interested in taking anything from her by force."