If you saw a deer that was shot by a poacher out of season, and there was 0% chance of survival, would you ease the pain and shoot it?
In the context of your question..NO. If I were to shoot the animal it is against the law here and could be charged which includes fine, loss of hunting rights for 1 year and permanent record. Furthermore if shot by a poacher originally I could also face charges of obstruction of justice and the above mentioned infractions. What I would do is call the TIPS line and help the CO's in anyway I could.
Ethically I think we all know what we would want to do in this situation but legally it could nip you in the butt.