I understand that when writing a dynamic television show like this, the audience must be anticipating anything and as such it is necessary and most interesting for certain characters to be killed at unsuspecting times. I'm curious, from the writers standpoint, why both Boone and Shannon were killed. It seems to me that it's much more interesting to have one of them remain, playing off the emotion and flashbacks with the other one. But to kill both of them? It makes me wonder if it was completley a writing decision (if so, i'd really love to understand why) or if there was an extrinsic factor here that led to the decision to have them both be killed.