She walks out of that room, to work again, and nothing can touch her. Nothing can bring her down, nothing will stop her plan. She's not sure why she believes that child so fully. It was nothing but a dream, after all. But Caffrey's plan will win and even if she won't be there to see it, Earth will be safe.
Cavennaugh stops her in the corridor, says she looks weird. She leans up and kisses him on the mouth, just like she did once before, and walks on, leaving him smiling, leaving him with hope, like the kid gave her.