I am not speaking about all of you: This is the third time Jesus mentions that Judas will betray him (13:2, 11). This matter deeply "troubled" Jesus (13:21).
I know whom I have chosen: This does not mean Jesus only chose the 11 disciples and excluded Judas. Jesus chose Judas and gave him every opportunity to believe. He realized that Judas had chosen the darkness instead of the light (6:70).
The one who shares My bread has lifted up his heel against Me: Eating together was a cultural symbol of personal intimacy, which made Judas’s betrayal all the more serious.