I don't think
BuuPlays saw this scene as light or dark when creating it, i assume it was meant as explanation what Eliza had become after turned into a vampire. You can clearly see her lust for blood as she is thirsty and her getting despaired after she realized having killed an innocent person (it maybe had been better for her to save the maid from a murderer and get his blood, so the one dying had been a bad person). IMO the intention was to show that Eliza still is a good person and has to fight her new being to keep human at least partially.
At least, the (mostly) overall reaction here shows that, even it's only a game, most players (here) care for Eliza (and maybe also the MC) and refuse to see her as a killer. As the MCs first companion and LI and minding her history and fate, she seems to be the symbol of the good way for some (or the most), making her (even when she doesn't it on purpose but accidentally) killing someone (not evil) will be refused by their minds.
As i said, the solution is to decide using the path the player had been chosen for the MC or (like
BuuPlays already mentioned) let the player decide in the scene (maybe some kind of threesome decision, full stop and partially stop on the light path, partially stop or don't interfere on the dark path). I think both solutions will work to please the players.
