Meaning that instead of Isobel's death being treated as an actual accident in terms of the story and the MC acting accordingly, killing her directly will instead treat it as a treacherous murder by having the MC lie to Jaheira about it (plus I'm not sure if Tav gets this dialogue, but Dark Urge gets to confess to Jaheira way later if they killed her).
Considering that Padzi is roleplaying a neutral character; it's an important distinction to make because one is treated as an accident by the story, while the latter an outright murder.
