He was offered two options. Finish his assignment and return to the guild house with his honor restored, or be banned from the guild in dishonor. If he would choose option 2, he would be given a three day head start and would then be hunted down by the guild. If he could survive for one year, his debt to the guild would be considered to be paid-off. No one that had been banned in this way had ever survived that year.
Pipper could not choose option 1.