Downside of having predictable momentum, brother: NOM. Grind grind grind grind.

Being literally eaten by his brother was not how he wanted this part of his day to go! Especially given that now he's back at ground soup level, where the miasma is thickest. Right now he's trapped half-in, half-out of Sesshomaru's maw, in pain.

Plan A: Claw Sesshomaru's muzzle, since this stupid piece of metal is useless.

Nope.

Poke him in the eye with the dumb piece of metal that can't cut a turnip?

That works!

Then Inuyasha will shortly after drag his way out of his father's corpse onto the plateau overlooking it, looking much the worse for wear, what with all the blood, the poison, and the coughing.

And Sesshomaru, who does not seem to have been actually inconvenienced more than momentarily by the eye-poke, will leap right after him.

Kagome has been catching her breath at the top of the great demon corpse's armor. This also gives her a chance to do a little bit of assessing the situation.

If the sword won't work for him, Inuyasha's not going to win.

If he's not going to win, then the only way she might get out of this is to run away. It's possible - not likely, but possible - that she can find some place to hide from Sesshomaru, and that he won't care enough to scour the entire area. Giant skeletons ought to have lots of places to hide; there's probably some crevice somewhere where she might be able to wait this out.

As soon as she's formed the plan, she can see what makes it unacceptable. She can't just run away and abandon Inuyasha. That would be real cowardice, in a way that merely running away isn't. If she's going to run and hide, she has to try to get him away, too, even if it makes her own chances worse.

That's how it is, then.

She takes another deep breath, and looks around to assess her options. Most of the skeleton is below her, but far enough below her that trying to jump off the massive shoulder pad is likely to result in her breaking her legs. Climbing down would take her past the ribcage again, and the ribcage is still full of poison. The only thing above her is the skull, which does form something of a shielded area. Massive as it is, Sesshomaru might be able to get in through the eyes, but he might have a harder time getting to her if she can crawl inside the nose. As in the ribcage, there are some great dead vines snaking into the skull. 

It takes her a couple more minutes to make the climb, but she does it, calling on her last reserves of strength. There are enough fighting sounds coming from outside to tell her that Inuyasha is at least not dead yet, when she pokes her head out.

"Inuyasha! In here!"

He'll do a series of hops up to about where she is.

"What?"

He's bleeding, he's limping, and he's coughing off and on, and the sword is still just a dented piece of metal. Whoever is winning, he very clearly isn't.

"Get in here," she tells him, and then takes a deep breath.

"You have to run away."

"Never!"

"You're gonna die! We're both gonna die if we don't get out of here!"

"I can handle my brother!" he says, as a gigantic roar shakes the corpse-mountain. "You get the hell out and let me handle this!"

"How am I supposed to get out of here if you're dead?!"

And all at once it is too much. She is in a skull inside a pearl inside an eye inside a dream inside a fantasy inside a well, helplessly watching the boy who threatened her life four days ago bleed out from his wounds and tell her it's nothing, and there is nowhere to run and nothing to fight with and nothing she can think to do, and the place where she's been shelving her fear has filled up while she wasn't looking at it.

There is no warning, before the tears fall, and at this point she doesn't think she cares enough to stop even if she could.

"You - shut up! Stop crying!"

"Why should I?!"

"Because I'll protect you! Do you hear me?"

(The Tetsusaiga pulses in his hand.) "Just sit tight and I'll stop him!" 

- oh.

There is, realistically speaking, no reason to believe him.

A part of her does anyway.

"...okay."

And, the sword in his hand seeming a much more natural part of it, his wounds hardly slowing him down, Inuyasha will turn and stride out of the great skull.

While at the base of it, Sesshomaru, muscles couched for another leap, springs, his aura of venom all around him and his claws and fangs ready - 

She stays huddled inside it - she agreed to sit tight, after all - and watches, not realizing that she's holding her breath.

And Sesshomaru leaps, his form power and speed in the harsh light of the sun -

And Inuyasha chops his brother's left arm off, simply and effortlessly, with the monstrously gigantic fang-like blade in his right hand.

His second blow will be across his brother's chest, and blood will flow from both.

And Sesshomaru will fall back, his great body twisting as he falls down, down, and down.

"M-m'lord! Wait for me!"

And Jaken will fleeeee after him.