I'm just gonna go ahead and say that I adore the the underground scene.
At first glance it's nothing special. Girl finds mech in underground setting tehe~
But there is so much depth here. First of all she wants to go above ground to help her friend/sister/love. Even while seriously injured.
But doing so she gets a flashback of... that person... telling her that she only befriended our lovely little sister because she needs strength to survive. Said person whose name I've forgotten is probably projecting a shit ton of her insecurities on her while saying this.
But anyway. She gets to the robot and it calls her master, once activated.
Not even a few panels ago we had a flashback where it was either implied that she feels like she tricked our little giant into being her sister, for her own benefit, or their relationship might have actually started out like that.
If she was actually as bad of a human being as she probably thinks she is, she would not reject the title of master that quickly.
It's a robot, sure it talks humanoid and acts like it, yet there is no proof it truly passes some form of isekai turing test.
For all intends and purposes chatgpt over here calling her master is not something she has to brother about.
It does not reflect on her mortality at all.
But she chooses to tell them to call her onee sama. the very thing that, she was accused of using to manipulate little giant into being her little sister.
The similarities are clearly intentional.
Yes she finds a weapon, but she chooses to love it. To view it as a friend, an ally.
Someone worthy of respect.
She even draws from other works of fiction to explain it.
She is stranded all alone in another world (the island), but she finds people (the little boy) that stay by her side in this crushing loneliness. Which is why she rejcts that notion of the book that her only friends should call her master, just because of a small difference of from where they come, who they are.
This one undergound scene gracefully backslapped every isekai slave owner trope to ever exist. past, present and future.
Fantastic