At its heart, Arrow's entire story involves a guessing game on multiple levels. Detective Lance and the rest of the Starling City Police Department, as well as Roy Harper, are still trying to guess at who the Vigilante really is, for different reasons. Up until last week's episode (“Darkness On the Edge of Town”) Oliver and the rest of the good guys were still trying to guess who was behind the Undertaking. Laurel's trying to guess at whatever it is Oliver's hiding from her. Everyone has questions, but the best they've got are guesses.
But for the season finale, almost all of the crucial guesswork has been addressed – Oliver and Malcolm Merlyn now know each other's secret identities, and Oliver now knows that Malcolm is behind the undertaking and his mother Moira had a hand in it – and what's more, the guessing game had been foisted on the audience: it was revealed, heading into the episode, that a major character was going to be killed off.
So you can imagine what I was trying to do for the entire 42 minutes of the episode. I'd been paying close attention to who does what and who goes where, making a note of all the dangerous situations that could be gotten into. It was not easy, because the writers did a brilliant job of creating distractions, by providing two actual near-death experiences: Oliver and Diggle go after Malcolm, and the Undertaking was pushed up, creating a huge earthquake in the Glades sooner than our heroes expected.
I came up with five names, listed in order of feasibility: Diggle for accompanying Oliver, Thea because she was in the Glades when the earthquake hit and so that Roy could take the Speedy nickname in her honor (but then I remembered this was a universe that did not use the traditional superhero names), Moira for revealing Malcolm's plan at the last minute, Roy for also being in the Glades when the earthquake hit, and as much as I was reluctant to include her in the possibilities, Laurel, for the previous reason.
The greatest surprises are those which emerge from truly out of nowhere, hidden under a fog of false certainty so thick; and in this episode, the writers really pulled off a brilliant one. I counted five possible deaths, and normally there is only one red herring in the equation. What I – and a lot of other people, it seems, going over the fandom on Tumblr – failed to consider, or maybe just didn't want to consider, is that given what was happening in the city, just about anyone in the show could've died. That's the second-biggest achievement here, really, that they managed to use everyone who were in danger to divert attention from the only person who seemed to be safe... in order to kill him off.
I said second-biggest, so here's the biggest achievement: they managed to build up a character to the point that a lot of viewers really did care about him by the time we got to this episode, and because of that, impaling him on a piece of rebar elicited a huge reaction from the community for that particular moment. One can say that it was a negative reaction, but the good kind of negative reaction – not the kind that tears the show down on its lack of merit, especially in ordering a death like that (although people have a lot to say about Laurel, and I'm just not one of them) but the kind that is actually grieving, wailing, “Why did you kill off one of my favorite characters?” because he had been written so beautifully, and not to mention there was still unexplored territory for his growth – or descent, whatever the case could have been. We'll never know now.
Because Tommy Merlyn was the success story for Arrow. A lot of characters in this show, despite its rather slow start (I already gave up on it after the second or third episode, but my family wanting to watch it brought me back) are being written well, but Tommy was a masterpiece – and he probably wasn't even done yet. It's pretty damn impressive the way he came up from an unassuming role player at the start of the show, a stereotypical rich kid's best friend, to being believable as one of its central pieces. He was integral because he provided logical tension to the Oliver/Laurel relationship, and an important piece because his descent heavily implied that after Oliver finally finished Malcolm, Tommy would emerge as his next archnemesis, the same way Vivian McArthur did in Chuck, and Harry Osborne did in Spider-Man. We felt that there was still a story yet to be told. We don't know how Tommy would've done it, but we thought he would.
So in that regard, it probably wasn't worth it for him to die a hero, because living long enough to see yourself become the villain is much, much more compelling. That's why Harvey Dent as Two-Face exists, that's why Aldrich Killian as the true Mandarin happened, that's why Loki turned heel in the first place. As consumers of the fiction, we are shrewd in wanting bad things to happen to good people just to picque our interest, so let me say this, given what we were given: I was proud of Tommy for going down there and saving Laurel, even if Oliver could do it better, even if he managed to get there first. Some of us, including myself, like the metamorphosis angle better, but the good that happened here is definitely also worth recognizing and applauding.
In fact, let's not forget that Tommy did have a metamorphosis anyway – it may not have been what we envisioned, but it is what we got and what we loved, and that's why we were shocked, that's why we mourn this death in the first place. If we must find something good and beautiful to take away from this, his final sacrifice capped off a wonderful transformation – one that, it should be noted, nobody at the very beginning ever guessed would happen.