There are several things that don't add upp with the season 5 flashback. For example in the season 6 premiere it was revealed that Brandon and Valerie never had sex because the minute they took their clothes off they started laughing. It was a mutual descision and they both agreed that it would feel too weird for them to hook up. While in this episode Valerie states that she did everything to get Brandon in bed but he was the one who refused. She said that this happened when Brandon came back inside after having talked to Kelly. So when did they take their clothes off? They didn't do it before Kelly showed up and it would seem weird that Brandon (and Valerie) would take their clothes off after he decided that they should remain friends.
This episode contains a flashback to the season finale of season five, which ended with Brandon and Valerie kissing on the couch in the Walsh house and, presumably, having sex. However, in the flashback, there are clearly some things which are different; for example, Valerie is wearing different shoes (black combat-style boots in the original, white tennis shoes in the flashback) and when they begin kissing in the flashback, Valerie straddles Brandon. But in the original scene he pulls her across his lap and she is sitting on his lap with her legs off to one side while they kiss. Also in the flashback, Val shows up at the door behind Brandon with her blouse unbuttoned, but in the original she is wearing a pullover top with no buttons.
"All That Jazz" is a song from the musical Chicago.