को: Stimulus ~> Theme
When the agent of the verb is construed as an [ss Experiencer], and the object marked by को is somehow providing that experience.
* [gex 001 "{मैं I} {एक one} {फ़िल्म film} {[pspecial "को" hi/ko Stimulus--Theme] DAT} {देख watch} {रहा stayed} {था was}{। .}" "I was watching a movie."]