The strategy guide and several walkthroughs suggest that if you side with Alarhî it should be possible to get Rinatto to leave Twin Elms by choosing cage + dexterity/constitution/resolve option, but the only way I manage to accomplish that is with lie + might option, which doesn't fit my character in the least. And yet, every other combination leaves him dead. As far as I can tell there is no conversation choice that mentions being a Watcher at all.

Hello Ansku,

 

This is all by design and working as intended. 

 

Thank you for your support.