I was in college, but had the same reaction. I'm surprised you remember something from that early, though I will say that it is intense. We tried to show it to our nephew at 5 or 6 but it freaked him out. It's simple enough for a kid to follow and so so scary at the top. I can see that making an impression on a tiny Sarah.

The long wordless sequence on the island (could it be 20 minutes? That's what I have in mind) where Alec befriends Black is one of the most beautiful and confident in cinema. LOVE this film.