And just who would that have been that died in the transporter for that one-off scene? Chekov? Sulu? Uhura?
"Matt Franklin" was chosen precisely because it was no one we would have cared about. The episode was about Scotty, not about someone else that we have an emotional attachment to just being told that they're dead.
But they had all been dead by the time anyways.
How can you be sure of that? McCoy and Spock lived through the intervening years the hard way, after all.