Looking across the picture from left to right:
* Bartholomew, James Minor and Andrew form a group of three. All are aghast, Andrew to the point of holding his hands up in a "stop!" gesture.
* Judas, Peter and John form the next group of three. Judas, you will note, has his face in shadow and is clutching a small bag (of silver?). Peter is visibly angry and a feminine-looking John seems about to swoon.
* Christ is the calm in the midst of the storm.
* Thomas, James Major and Philip are next. Thomas is clearly agitated, James Major stunned and Philip seems to be seeking clarification.
* Matthew, Thaddeus and Simon comprise the last group of three figures. It appears that, when a situation turns ugly, Simon is the "go to" guy for explanations.
So, John is the "woman."