Why didn't General Martok receive discommendation, due to being captured by the Jem'Hadar and failing to commit suicide?
Klingons are allowed (by honour) to not commit suicide if there's a reasonable chance that they'll be able to escape from their captors. Much like the 'bad apples' of Colditz Castle, prisoners that require guarding are also tying up their enemy's resources.
GARAK: Aren't you Klingons supposed to kill yourselves when you're taken prisoner?
WORF: Not when there are still enemies to fight.
MARTOK: Or hope of escape. If you are Worf then you must be Garak. He said you would come.