In the real world if a person is a danger to themselves or someone else, then they are locked up. Just consider it Feyre being put on a 72 hour mandatory hold. She was determined to endanger herself and then others would be in danger trying to protect her. She was the one in the wrong here.
"I was about to turn down the hall that led to the study, determined to ask Tamlin if there was any task that I might perform, ready to beg him, when the study doors flung open and Tamlin and Lucien emerged, both heavily armed. "
So, whatever battle they are going into is going to be bad enough that a powerful High Lord needs to be heavily armed on top of his own powers.
"Tamlin’s face was a grim mask as they approached. “There’s activity on the western sea border. I have to go.” The one closest to Hybern."
So, it is an urgent matter of "national" security and he doesn't have time to negotiate with Feyre
“Can I come with you?” I’d never asked it outright, but— Tamlin paused. Lucien continued past, through the open front doors of the house, barely able to hide his wince. “I’m sorry,” Tamlin said, reaching for me. I stepped out of his grip. “It’s too dangerous.” “I know how to remain hidden. Just—take me with you.” “I won’t risk our enemies getting their hands on you.” What enemies? Tell me—tell me something. I stared over his shoulder, toward where Lucien lingered in the gravel beyond the house entrance. No horses. I supposed they weren’t necessary this time, when they were faster without them. But maybe I could keep up. Maybe I’d wait until they left and— “Don’t even think about it,” Tamlin warned. My attention snapped to his face. He growled, “Don’t even try to come after us.” “I can fight,” I tried again. A half-truth. A knack for survival wasn’t the same as trained skill. “Please.”
SO... as the leader he tells her its a time sensitive mission and she keeps on, plans on following, and lies about her skills.
He shook his head, crossing the foyer to the front doors. I followed him, blurting, “There will always be some threat. There will always be some conflict or enemy or something that keeps me in here.” He slowed to a stop just inside the towering oak doors, so lovingly restored after Amarantha’s cronies had trashed them. “You can barely sleep through the night,” he said carefully. I retorted, “Neither can you.” But he just plowed ahead, “You can barely handle being around other people—” “You promised.” My voice cracked. And I didn’t care that I was begging. “I need to get out of this house.” “Have Bron take you and Ianthe on a ride— “I don’t want to go for a ride!” I splayed my arms. “I don’t want to go for a ride, or a picnic, or pick wildflowers. I want to do something. So take me with you.”
Yes, because a trip to battle will soothe her nerves and be better than finding something productive to do at home until he handles the crisis and they can talk about what to do next.
That girl who had needed to be protected, who had craved stability and comfort … she had died Under the Mountain. I had died, and there had been no one to protect me from those horrors before my neck snapped. So I had done it myself. And I would not, could not, yield that part of me that had awoken and transformed Under the Mountain. Tamlin had gotten his powers back, had become whole again—become that protector and provider he wished to be. I was not the human girl who needed coddling and pampering, who wanted luxury and easiness. I didn’t know how to go back to craving those things. To being docile.
I guess you figured out how to be that person again in NC with a giant mansion and servants and slums in Velaris and leaving the people trapped in Hewn. And letting Rhys threaten to kill Nesta, and lie to you about the baby.. huh...
Tamlin’s claws punched out. “Even if I risked it, your untrained abilities render your presence more of a liability than anything.” It was like being hit with stones—so hard I could feel myself cracking. But I lifted my chin and said, “I’m coming along whether you want me to or not.” “No, you aren’t.” He strode right through the door, his claws slashing the air at his sides, and was halfway down the steps before I reached the threshold. Where I slammed into an invisible wall.
Ok, so he tells you its dangerous and that you will put those around you in danger and you still want to go.
I was trapped inside this house. I might as well have been Under the Mountain; I might as well have been inside that cell again—
No, a mansion and in the lap of luxury is really really different than a cell UTM. I mean I get she was panicking but come on...
