Please instruct the meaning of "living inside a lobotomy"

[chebu]

Could you please instruct the meaning of "living inside a lobotomy".

This expression is from a novel "The girl who stopped swimming"

Laurel, the heroine of the novel, is a conservative housewife and expecting a baby at nineteen. Thalia, her elder sister, is unconventional outgoing woman.

Following is from the novel.

Laurel started to get out, but Thalia put one hand on her arm, stopping her."Seriously? This is what you want? This house, this husband, a baby at nineteen?" Laurel nodded, and Thalia let her go. But Laurel heard her mutter under her breath, "It's like you're living inside a lobotomy."
"Oh, stop it," Laurel said.

Your help will be highly appreciated.

[Anglika]

A lobotomy was a treatment for mental disorders, no longer used much, which removed a part of the brain. It left the person lacking in energy or initiative and removed much of their character.

The suggestion is that Thalia thinks her sister is lacking initiative and has allowed herself to be caught in a trap.

[chebu]

Dear anglika

Thank you for your help again! :)