Rave lights halo Maze's head when she reverts back to being her true self. Comically, it's when she admits she doesn't care about some stranger's personal tragedy.
Lucifer suggests whiskey to quiet Charlie. It's a old wives' remedy that whiskey rubbed on the gums helped with teething.
Second time in 5a Lucifer's home bar wall is lit up in green. In both instances, meaningful details of a main character's past from before they met each other are brought to light.
At the beginning of the episode, after Chloe and Lucifer arrived at the scene at the same time, Ella asks Chloe "Did you guys come together?" The phrasing of this is no doubt a callback to "The Angel of San Bernardino (S3E20) where Chloe said something similar after sex with Marcus Pierce. Its fitting after possible implied sex with Lucifer (though moments later we find out they did not because they got called to this scene) "Lucifer Morningstar: Will he be coming with you from now on? Because he is killing our banter. Chloe Decker: Absolutely not, no. Pierce and I only came... [Realizes what she just said] Chloe Decker: Drove together just this one time. One time."
The opening and closing scenes are similar, having a couple being intimate together.