Verloc is complacent about Winnie’s love for him until the very last moment of his life—hence his relaxing on the sofa. When Winnie kills Verloc, he rests in a vulnerable, trusting state, invoking the way Stevie trustingly submitted himself to Verloc’s guidance and instruction. For her part, Winnie’s act is an outburst similar to Stevie’s: a vulnerable person has been hurt, and she lashes out violent because there is nothing else she can do to fix the situation. She pays Verloc back for his betrayal of her trust.