Seeing his son's reaction and hearing Shaker recite a phrase exactly like the kidnapper did, Tom and Sean realize that Shaker is the kidnapper, but Shaker realizes that Tom is on to him.
Tom and Sean are seeing his son's reaction. Tom and Sean are hearing Shaker recite a phrase exactly like the kidnapper did. Shaker is the kidnapper. Tom and Sean realize this. Tom is on to him. Shaker realizes this.