My first thought was -
Keaton: You...you know!
Fa'lina: It's almost like I'm omniscient.
See, Keaton isn't experienced enough in hiding what she is.
Firstly, she's blatantly obviously scared as a result, totally shitting herself - not dropping a brick internally but keeping her outer view unworried. And yes, I bear in mind that at least some of that is that you can't show someone as unworried in a comic format if they're so scared they're ready to build a wall of bricks...
Secondly, she's not brazening it out at all - folds at the first sign of trouble. Which strikes me as somewhat unreasonable - anyone who has lied about anything for a few weeks has run into the problem of telling people that nothing is wrong while someone else buries a body behind the door, metaphorically speaking. You get this even with christmas presents.
Mebbe I'm just overly critical. Maybe Keaton just rubs me up the wrong way. Go figure.
'Cubi do tend to react emotionally by default. Also, it's likely the first time in quite a while that she's found herself in a situation she can't murder her way out of.