This episode reminds me of Remember Me from TNG but it also has an Outer Limits horror monsters vibe. It was a well told crafted that developed the Alara character who is facing an explicable variety of nightmares come to life. Only late in the episode does the audience find out that Alara is actually in a simulator (holodeck) and had used a memory block to avoid realizing it so she could understand and control her fears that might prevent her from doing her job. She did successfully face her fears although I was troubled by the ridiculous contrivance where Alara abused her authority as security officer to prevent the Captain from stopping the simulation. Apparently, there's a Directive 38 that allows the security officer to take control of the ship and she falsely invoked it. It seemed rather counter productive given the premise of the episode.