In the present rules on Strife, becoming Compromised, and Unmasking, it is not exactly clear when exactly the character can Unmask, mechanically. In specific, at what step of the process in taking an Action can a character choose to Unmask?
On Page 12 of the Beta, the steps of making a check are clearly delineated.
Determine Dice Pool, Determine TN
Assemble and Roll Dice Pool
Apply Advantages and Disadvantages
Choose Kept Dice