House Cleaning
Every few seasons, they do this, where they have some random mass killing attempt of the agents by some psycho.
And, in this case, the agents must know it's a trap and walk right into it anyway. Is this a way to cast off crew members that they didn't want on the show anymore? Especially since there's a constant revolving door on this show, you wouldn't think that they would need these "cliffhanger" endings/resolutions to get rid of people.