Some kind of emotional manipulation I think. They're giving her constant whiplash intentionally.
Aegir is basically dead walking, since she requires the Queen's blood to live and has a finite, limited supply of it with orders to never return.
She'll probably be a bargaining chip later when Hati realizes the Queen's a monster, but that killing her will mean the death of the children and assured death of Aegir.
That's a chapter alright, miss queen Imma need you to keep your incestual instinct out my Yuri please and thank you, there is only one true pairing here and your not involved and now I wish I used my hang pun here...