In reality he knows Melshi will be fine. They may not have bacta tanks, but they have patches, and one excellent medic on the tiny little base he's made for himself on the outpost here. He's more annoyed Melshi won't be able to come to Jedha, having definitely been his top choice for the final party.

"No." The ship isn't completely ready, and maybe he's still a little paranoid she might steal it and flee. He is going to constantly concerned about her disappearing on this mission. "You can wait in the mess hall, though don't expect much beyond simple rations. Or there's a room near the hangar, if you need to rest before we go. Someone will get you when it's time."

The picture of indifference is easy when it's a lie, because lying is easy.