'Person Of Interest' Season 4 Spoilers: Twitter Reacts To Amy Acker, Sarah Shahi Shocker! [WATCH]

Season 4 of Person of Interest delivered the second part of its epic and action-packed trilogy on CBS. The episode was shrouded in death as Twitter was filled with emotion while watching the shocking twist between Shaw (Sarah Shahi) and Root (Amy Acker) in 'If-Then-Else.'

In the first part of our recap, the Samaritan wanted to meet with Root and sent in its avatar. Seeing The Machine as a fallen God, Samaritan would take its place and promised to enslave humanity, in order to protect it. In the cliff-hanger, the Samaritan unleashed a virus onto Wall Street and forced the stocks trade to take a nosedive.

In the second part of our recap, the Machine had to come up with a scenario when Root and the others were trapped in a deadly shootout. After two simulations, the Machine predicted the deaths of Finch (Michael Emerson), Reese (Jim Caviezel), Fusco (Kevin Chapman), and Root. Running out of time, the Machine chose the third simulation, where no one in the team was sacrificed.

Unfortunately, Martine and her operatives arrived ahead of time. To save the team, Shaw kissed Root before sacrificing herself to save them. Root screamed as loud as she could as she watched Martine point her gun at Shaw's head.

Was that last noise audiences heard the sound of a gunshot? Shahi reveals to Entertainment Weekly, "I don't know if this is Shaw's end, per se, because the 61 million dollar question is, is she or isn't she dead? But given what's going on in my life right now, it would definitely be a challenge to go back with two infants and try to be present as the character and to meet the demands of the show. But who knows? It's definitely a goodbye for now, but not goodbye forever."

Check out Shaw Is Gunned Down here:

Here is what Twitter had to say:

@TheMattFowler states, "Just watched last night's #PersonOfInterest episode again and now I'm useless."

@AlexanderHaxton adds, "What a #PersonOfInterest ep 2night! The cast through the Machine simulations is part of the reason I love this show so much @POIWritersRoom"

@PoisonedHeart__ mentions, "This episode of #PersonOfInterest got my heart raising like hell !"

@Singhness describes that kiss, "Aww that Root & Shaw moment #PersonOfInterest"

@Hindsight21 writes, "#PersonOfInterest just broke my heart FOUR TIMES. But it also made me squeeze like the fanboy that i am. Good balance!"

Because Shahi is pregnant in real life, @the_forger expresses his gratitude, "@onlysarahshahi congrats on the good news! Sending love on behalf of all the #PersonOfInterest fans"

As does @Linesy01, "@onlysarahshahi congrats & all the best for motherhood but still can't believe your gone, hopefully it's just for now :D #PersonOfInterest"

Person of Interest returns Tuesday at 10pm on CBS for the third part of its trilogy. Readers, what did you think of If-The-Else?