Cassian didn't think to knock on the bathroom door, he just assumed no one would be in there, and if they were they would've locked the door. However, when cassians hand pulls down on the handle he opens the door to see you half dressed in your trousers and a bra.

For about a millisecond he's mortified and ready to apologise, but then he notices the jagged scars running along your arm, shoulder and back. He can barely hold back his fury as it erupts to the surface. He's overwhelmed by the urge to tear apart anyone who hurt you.

"Who did this to you?" He practically growls. He's not furious at you, he's furious at the person or people who would dare to touch you. In the back of his mind he's worried about you, he just wants to pull you into a hug and keep you safe from harm for the rest of your life. But at the moment all he can think of is shattering every bone in the body of the person who hurt you. He wants revenge.