Wait... So, now the princess is hugging another person, angry at the MC for dying?
Did someone seduce her with charisma and lies? Why is she so angry if she's the one who cheated?
I am getting mixed signals throughout this whole encountered story
She probably yelled Sea Dragon because it's a isekai disconnect thing. In Japan they usually yell "Umi da-~~" (It's the sea!), so unless it's a mistaken translation, it's their version of it