...Hmmm.
She knows maybe two facts about atronachs, she's the only one who knows how to pick locks, this is dumb -
She's also the only one who can heal herself, and one of the facts she knows about flame atronachs is 'idiotically aggressive.'
She jumps, catches a bit of stonework, pulls herself onto the tiny thin bit of decorative ledge around a column - then tosses her own fireball at the atronach before immediately jumping to the upper platform of the sanctum, tauntingly just outside of its direct line of fire. Hopefully it'll have to abandon the area near the emperor to attack her properly. (Hopefully it can't just fly and has to take the stairs.)
"Hey, fuckface!" she yells at it, glancing around frantically for some dead body or another to steal a ranged weapon off of that's better than her sling. If not: stones to reload said sling with. "Your fire sucks!"
And, of course, it attacks her - gets out of death explosion range of the emperor, and also it's fully willing to hit the assassins to get a shot at her - which means free meat shields for Lilou, especially if anyone tries to stop her from running around and distracting their atronach.
She takes pot shots at it - don't seem to do much, but that does keep it angry with her, so - and at the assassins, dropping one and hopefully throwing the others off - but she mostly tries not to get barbecued.
This involves a lot of flinging herself behind columns or to the floor. Her entire body hates her.
She gets enough pressure off the Blades it seems, though, that the quieter guard actually comes to help her - she hears a hoarse shout from one of the others but she can't look - the atronach catches up, she slashes at it with her dagger, which keeps it from preventing the quiet guard from stabbing it -
- This wasn't, it seems, a very durable atronach.
Lilou flings herself back off the platform, landing hard and painfully, as it explodes. She drops her dagger in the fall, starts scrambling to her feet, but it hurts -
But... The field is silent, except for the low moans of dying men.
Lilou takes a deep, shaking breath, and looks around to see if anyone else is still standing, as she tries to steady her hands enough to heal herself.