You don't have to kill Lae'zel but I can understand the urge to do so Situations like that can be handled quite peacefully.
The artifact changing it's owner happens in a rather dramatic cut scene, it is fully explained in story.
So it's another story flow issue. I haven't had that dramatic cut scene yet, so it isn't explained in story when I pull the artifact out of my pocket. I hope they fix this for future runs. Story flow problems are the worst to my mind. I'd rather have bad graphics or crashes.