You're wrong about River. River's not on the ship. They didn't want her here, but she couldn't make herself leave. So she melted... Melted away. They didn't know she could do that, but she did.
River ,'Objects In Space'
The Minearverse 2: Getting his words out.
"There will be an occasional happy, so that it might be crushed under the boot of the writer." From Zorro to Angel, this is where Buffistas come to anoint themselves in the bloodbath.