I get that some people didn't like the tonal shift of this episode and interruption of the main plot, but I loved all the Star Wars references/parallels.
El trying to pull the train car was obviously reminiscent of Luke trying lift his X-Wing in The Empire Strikes Back (except that El succeeded!). Kali essentially tempted El with the dark side of the Force by teaching her use anger to strengthen her powers. Kali even manipulates El into force choking one of "the bad men" almost to death before El has a change of heart.
In the end, El chose to use happy, loving memories (not angry, painful ones) to connect to her friends and, discovering that they are in danger, left Kali to save them. This is similar how Luke had a vision of Han and Leia in danger and left Yoda to save them.
The questions remaining after this episode: Is El walking into a trap like Luke did? Can Kali be redeemed? Will she return to Hawkins to help El? Would her powers even be effective against the demogorgons or the shadow monster?
