Being evil is more than simply killing everyone and throwing rocks at bears. That is being an asshole.
You could be evil and still save the tieflings and Halsin, provided they would work for you in return. Remind them in the future who saved them and why they should do such and such.
I once played a warlock that set a whole village against its mayor and put my minion in his place, the only person who died was the mayor and a few orcs I used in the process of agitating the village.
Imo, being evil is taking what you want with no care for others. That's far from let's kill everyone, which is what seemed line the evil path available. Didn't finish the evil play because it didn't feel like true evil and more like chaotic evil.