At the end in the cafe you could see cable reading the manga The Devil Is a Part-Timer High School Volume 5.
The character Bull, played by Michael Weatherly, repeatedly calls Abigail Walsh, played by Amy Rutberg, "Boss". In his previous show NCIS (2003), he referred to Gibbs, played by Mark Harmon, as "Boss"
WILHELM SCREAM: When Cable, Benny, and Chunk are playing the game, Benny's player dies with a Wilhelm Scream.