From the album Pylon
This is about someone who has convinced themselves anger is happening to them instead of being something they're choosing. The switchblade is introduced as self-defence but there's no actual attacker in the song, just open space, which means all that cutting is either pointed inward or at nothing. The fever framing lets her off the hook for deciding whether to fight or flee, because if it's a sickness then it's not her fault.
I'm a switchblade, cuttin' through an open space / Need a reminder, you start to feel like a graze
The weapon has no target. If you're cutting through open space, you're not defending yourself from anything real. The 'you start to feel like a graze' might be her talking to herself, which would mean even the wound is depopulated, just her and her own anger in an empty room.
Do you start the fight or take the flight? / Is it wrong or right to try to
The grammar collapses mid-question, like she can't finish the thought because finishing it would mean admitting she has agency. The question itself is the flight response, buying time so she doesn't have to choose.
Hold my lighter, courage flicker, burn and fade
Courage isn't a steady flame here, it's something that needs constant relighting and still dies out. The lighter replaces the switchblade but does the same thing, gives her something to hold while she waits for the feeling to pass instead of acting on it.
Can't control this fever / That just takes it out of me
She frames anger as something draining her, but the whole song is about how she won't let herself use it. The fever isn't taking anything out of her, she's refusing to let it go anywhere, which is maybe why it feels so exhausting. I'm not sure she realizes the trap she's in.
The song loops back to 'I'm a switchblade' three times in the outro like she's trying to convince herself the weapon makes her dangerous, but the whole song proves it doesn't. She's stuck in the question, which is safer than the answer.