ORS 161.219   a person is not justified in using deadly physical force upon another person unless the person reasonably believes that the other person is:
 (1) Committing or attempting to commit a felony involving the use or threatened imminent use of physical force against a person; or
 (2) Committing or attempting to commit a burglary in a dwelling; 

So, if you reasonably believe that the person is doing either (1) or (2), they may legally wind up "dead" instead of 'startled'.