Goes to show how much of a lazy/cheap hack Lucas is. Luke screaming as he fell down the shaft could’ve worked if Lucas’ gotten Hamill in to record it, or someone with a relatively similar voice. But no, he reuses the Palpatine scream 'cause he couldn’t be bothered to put the extra ounce of effort into it.
Actually no, he’s a genius and this is secretly art. It’s symbolic of how Luke is Palpatine, which makes sense if you watch the Original Trilogy backwards, as it was always was meant to be.