Well, it’s cliche.
Here’s the thing, every cliche began it’s life as a good idea that was executed powerfully. It caught people’s attention, dragged them in, and got them to pay attention. Then they took that idea home and used it in their own work.
And now it’s overused. The initial impact is spent, the power; dispersed, and the idea has been run into the ground. It’s not compelling or dramatic anymore.
Dying in someone’s arms is cliche. I’m not sure when or where it worked, but it’s been played to death and back. It’s been subverted with fake outs, it’s been reversed, it’s been played for comedy with someone holding their TV remote or baseball bat. Maybe there’s some weird combination that hasn’t been attempted, but we’ve all seen this way too many times.
Now, this isn’t the “it’s unoriginal, therefore it sucks” or that long chain of “I liked X better when it was completely-unrelated-thing-Y.” We’re all drawing water from the same well, so you’re going to find inspiration in the things you read and watch. But, you need to ask yourself if the story, and characters, actually benefit from what you want.
You’re asking us, which means, something about the scene bothers you. I’m going to suggest it’s not the realism.
The freedom in being a writer is having the opportunity to say, “not like this.” Just because someone else has written this touching scene with a character’s friend dying in their arms, doesn’t mean you have to.
What do you want for your story?
If it’s closure, then finding their dead body, is probably enough. Maybe, I’m a bad example, but, from my experience, closure, in fiction, is a bit unrealistic. Seeing someone die doesn’t wrap up anything, they’re still gone. Maybe it helps, I’m honestly not sure.
If it’s because, “this is what you do for a character”, then, no, you don’t need to. Which is more interesting: Your character not wanting to accept their friend is dead, despite the likeliness of it, or having them holding their dying friend in their arms? I’d vote for the former, personally.
Anyway, I know this’ll sound like BS coming from us, but if you don’t flat out kill someone, people can survive ludicrous amounts of damage. Surviving critical injuries, like arrow wounds, without medical attention is a bit of a stretch, and even surviving those wounds in a preindustrial setting could still lead to death via infection.
That’s the other route, you can go with, by the way. Your doomed character gets medical attention and then withers away and dies regardless because of a bacterial infection.
Depending on the story, it’s also possible she’s found by the other side, and kept as a PoW, and possibly turned against your character later. This’ll depend on the politics of your factions, but, it is an option. It’s not terribly original, but it is something you could work with, particularly in combination with the whole, “wanting them to be alive against the odds” suggestion above.