To complete the Tight Squeeze Challenge in Lego Star Wars: The Skywalker Saga, you need to discover a shortcut via the Protocol Terminal during the Ground A-salt level in Episode VIII – The Last Jedi. Unusually for a level Challenge, Tight Squeeze cannot be completed when playing in Story mode, so if you want to get it, you’ll have to complete the level at least once, then replay it in Free Play.
The level begins with you playing as Luke Skywalker (Old – Crait) and locked in battle with Kylo Ren, but this part of the level is little more than a QTE (quick time event) boss battle. You need to distract Kylo Ren to complete the Ground A-salt level and finish Episode VIII – The Last Jedi, but the meat of the level takes place inside the Crystal Cave.
How to discover a shortcut via the Protocol Terminal in the Ground A-salt level
Halfway up the stairs to the west of the center of the Crystal Cavern, there’s a Protocol Terminal. Switch to a Protocol Droid (for example, C-3PO) and use the terminal to gain control of C-3PO (Rusted). Go down the stairs (as Rusted C-3PO) and use the Protocol Terminal to get the password for the Crait Service Tunnel Doors. Continue to the bottom of the stairs, go past the crate with gold bars, and access the red Protocol Terminal. Input the Crait Service Tunnel Doors password here and the Crait Service Tunnel Doors will open, creating a shortcut through to the Emergency Doors and completing the Tight Squeeze Challenge.
Completing the Tight Squeeze Challenge is especially important, as it opens up the part of the Ground A-salt level that you need to access in order to complete the Knock-Knock Challenge, and to collect all five of the Minikits that can be found in the Crystal Cave.