I'm not sure one can call it a "saving grace," but Zadu's pragmatism seems to extend far enough that I don't see him gunning for Noor in the future...unless hired to do so.
Noor and Ines prevented him from completing the task he was hired for, true enough.
There wasn't any personal animosity involved on Zadu or Noor's parts.
Ines...was also doing her job.
I'm pretty sure that's how Zadu will look at it.
He did his best to fulfill his commission, no one can question that.
There's no profit in seeking "revenge" over his "humiliation" when he doesn't consider himself humiliated.
Ines understands that shields aren't just for defense.
You can bash people with them.
Ines's primary duty is protecting the Princess.
By extension, aiding someone who ups the Princess's survival probability falls within her remit.
What matters is getting the job done.