Seeker of Slaanesh Threat Card Clarification
The card is not intended to include any extra "loss" effect. In other words, if you lose the battle you still just lose 1 Life like normal without taking any additional effect. 

In addition, the statement of "If you do not…" in the "win" effect is in reference to whether or not you discarded a Corruption card from the first effect. If you have no Corruption cards to discard or choose not to discard one, you draw 1 Corruption card.