Bartholomew, James, son of Alphaeus and Andrew form a group of three, all are surprised.
Judas Iscariot, Peter and Mary/Jesus's impregnated wife form another group of three. Judas is wearing green and blue and is in shadow, looking rather withdrawn and taken aback by the sudden revelation of his plan. He is clutching a small bag, perhaps signifying the silver given to him as payment to betray Jesus, or perhaps a reference to his role within the 12 disciples as treasurer.[8] He is also tipping over the salt cellar. This may be related to the near-Eastern expression to "betray the salt" meaning to betray one's Master. He is the only person to have his elbow on the table and his head is also horizontally the lowest of anyone in the painting. Peter looks angry and is holding a knife pointed away from Christ, perhaps foreshadowing his violent reaction in Gethsemane during Jesus' arrest. Mary looks like sh knows something that the other don't and has a slight smugness to her.
Jesus.
Apostle Thomas, James the Greater and Philip are the next group of three. Thomas is clearly upset; the raised index finger foreshadows his Incredulity of the Resurrection. James the Greater looks stunned, with his arms in the air. Meanwhile, Philip appears to be requesting some explanation.
Matthew, Jude Thaddeus and Simon the Zealot are the final group of three. Both Jude Thaddeus and Matthew are turned toward Simon, perhaps to find out if he has any answer to their initial questions.