Are all the books school appropriate?

The Narnia series were some of my favorite books growing up, so I decided I want to read them to my third graders now that I'm a teacher! I bought The Magician's Nephew and The Lion, the Witch, and The Wardrobe because I specifically remember my teacher reading those two to me so I know they are appropriate for a read aloud. However, I read one of the others on my own later and I have a very vague memory of someone trying to stab themselves? From what I remember it was a pretty intense scene, to the point where it stuck with me all these years. So, are all the books in the series appropriate for a third grade audience or would you recommend I pick and choose if we end up wanting to read more of the books?