She had done all that because she felt that Carter cared for Shirley. She realized that Shirley was a threat to her, so she paid someone to kidnap Shirley, who was locked up at Jeremy's old villa at the time.

Using Madeline's name, Ada had ruined Shirley's face and injured her leg. Consequently, Shirley had been hit by a car in her attempt to escape, which led to her disabled legs.

The whole thing began because of her jealousy!

"Just you wait, Adam. You're as annoying as your sister Shirley!