Star Trek Discovery Episode 106 "Lethe"
An assignation attempt goes wrong and Burnham (and us) learn how she lost her attempt to get into the Vulcan Expeditionary Group.
Episode 106: Lethe
On his way to broker a peace deal with renegade Klingon houses, Sarek is injured when a "logic extremist" attempts to assassinate him. Burnham senses this, and Lorca agrees to rescue Sarek. Admiral Katrina Cornwell questions this decision and others that Lorca has been making. Burnham searches for Sarek in a shuttle with her roommate, Cadet Sylvia Tilly, and Tyler. Burnham attempts to connect with Sarek's mind, and finds him remembering the time that her application for the Vulcan Expeditionary Group was rejected. She learns that the VEG would only admit one of Sarek's children, and he chose Spock, his half-human son. Spock ultimately chose to join Starfleet, rendering Sarek's decision futile. Burnham helps him regain consciousness and activate a locator beacon. Lorca and Cornwell sleep together, but she is concerned by his paranoid behavior and plans to take his command off him. With Sarek unable to meet the Klingons, Cornwell takes his place; however, the peace talks are actually a trap, and she is taken captive.