One of the most interesting things that has been revealed since the release of Avengers: Infinity War is the revelation that the film-makers chose their victims carefully. There was nothing random to Thanos' snap, no matter what the Titan claimed as part of his plan to rebalance the universe.
In every case, the characters who died were chosen carefully, sometimes to serve the story of Avengers 4 and sometimes for maximum impact on the survivors. In that fiendishly clever way, the Russos managed to make the survivors victims of the snap too, which takes a special kind of emotional terrorist.
So how did they choose who would die?
How They Died
The SHIELD veterans were clicked out of existence in New York in the aftermath of Thanos' snap, but not before Fury managed to send out a distress call to Captain Marvel.
WHY They Died
The reason here is two-fold: firstly, Marvel needed a way to foreshadow Captain Marvel's arrival with a little added drama, and Nick Fury was the obvious candidate given his link to her in her own movie.
But secondly, and even more importantly, Fury and Hill are vulnerable human characters and the Russos needed to show the true cost on a global level of Thanos' snap. So we got to see the mass casualties of that fateful moment through their eyes as they died too, which was a very clever dramatic decision.