EP Jonathan Nolan gave these spoilers to TV Guide on how the upcoming death will affect our heroes for the rest of the season:
"We're talking real damage here," executive producer Jonathan Nolan tells us, hinting that someone may act out as a way to deal with his or her grief. "For the first time, a number comes up [and] the perpetrator might be one of our own team. That's a fresh wrinkle on our show and points to the fallout from all of these events." Even worse, the team may no longer be able to rely on each other. "It will pull the team apart a little bit," Nolan says. "This season is about uncertainty and sacrifice, and we're kind of out in the wild blue yonder in the second half of the season."
Person of Interest continues its 3-episode arc next Tuesday with "The Crossing" at 10 pm on CBS.