Every episode of Fringe contains a hidden "next episode clue" that foreshadows something in the following episode. In the last Fringe episode "A Better Human Being", a chalk board at the Deerfield Hospital appears to have the words "Box Springs" written on it...
In the Fringe episode "The End Of All Things", Robert Jones attempts "evoking an emotional response" out of Olivia by electrocuting Nina on old mattress box spring, a go-cart battery, and some jumper cable.
This reminds me of a quote from the sci-fi classic Blade Runner:
HOLDEN: They're just questions, Leon. In answer to your query, they're written down for me. It's a test, designed to provoke an emotional response... Shall we continue?FYI, According to the EnglishForums.com, while 'provoke' and 'evoke' are generally synonymous, they differ in the source of the emotions. Evoke calls the fear from within us, whereas provoke causes/gives reason for the fear.
[Transcript for "The End Of All Things" from Fringepedia.net]