Yoda Is Your Father said:
What about that idiot who decided not to fire on the escape pod because it didn’t contain life signs? Were they trying to save ammo or something? In a world where artificially intelligent droids are commonplace… fire on the damn escape pod!“There goes another one”.
The presumption was that they had fired on other escape pods and it wasn’t worth the hassle anymore. How many escape pods went off? Three? Fifty? We don’t know, but if there were a ton of them and none of them had lifeforms on board, it’s not a stretch to imagine the officers would tire of worrying about them.
Yeah I know, and you’re right. I don’t actually have a problem with the ‘no life signs’ escape pod bit in ANH.
But my point is Imperial stormtroopers, gunners, pilots and even officers have proven themselves to be a bit, shall we say ‘less than amazing at their jobs’ time and time again throughout the OT, so claiming that everybody in Ren’s unit would have been the ‘best of the best’ is a stretch.
Besides, when we see Finn in action later in the film he is kinda badass - he knows how to hit a target (which is more than most stormtroopers), has no problem killing enemies when they pose an actual threat (i.e. they’re not unarmed villagers) and he’s pretty brave going up against Kylo Ren (when he’s just seen Rey get force-thrown against a tree and knows he’ll probably be beaten). He has clearly been well-trained. His desertion is, in my opinion, a moral choice, and a believable one at that. The First Order’s brain-washing of children can’t overcome the natural good in them… and isn’t that in line with the whole ‘light vs dark’ theme of the whole saga?