Olivia contacts Nina Sharp discreetly, asking for her help; she promises to meet them away from the Ministry of Science.
When Nina does not return, they turn to the storage facility where the sublimation device, previously used by Fringe to access an old laboratory ("Five-Twenty-Ten"), had been taken from, and start probing all the workers there, including Dr. Hastings (Gabe Khouth), who had helped the Fringe team earlier.
Windmark starts to probe her, and explains that the child is really just an anomaly, XB-6783746, from the Observer's time in the future that was to be destroyed before he was taken.
Windmark orders the Loyalist agents to restrain her for him to run a deeper probe, but she grabs one of their guns and kills herself.
By the time Olivia, Peter, and Walter have returned, the lab has been ransacked, and Nina's body remains.
Olivia and Walter mourn their loss while Peter notes from security footage that she killed herself to prevent her mind being read.
He noted the final act was "full of action, revelations, stylistic filigree, and rich emotion."