Our brave adventurers caught Tsuto unaware in the basement as he was writing in his diary. After a brief fight, having Tsuto flip a table to protect himself from the sorcerers burning hands, he was captured.
While the players were interrogating him on the spot I rolled his escape artist check and he maxed out on his initiative. He then stole a PCs dagger, aced his will save and stabbed himself.
The real kicker - the PCs dagger was already coated with poison. So Tsuto died a turn later, the cleric being out of spells and failing a healing check. But not before he declared how he "Did it all for her." and that "She would bring him back.".
I might bring him back for when they face Nualia.