You lose the XP, but keep the experience.

You try to run away, but your short legs only get you so far before an arrow pierces your back, causing you to fall to the floor. You don't give up, attempting to crawl away, but once you feel a second arrow hit, your health bar reaches zero and you die.

You respawn some time later in your intended part of the dungeon, frustrated to lose the XP and the chance to explore the dungeon. But you comfort yourself with the knowledge you gained: You get XP from monster kills as well. To think you never tried that. You always assumed that your debuffs couldn't be used on allies, and never bothered checking since it would be very rude. But apparently you can in fact not only use your debuffs on them, but it even follows the XP-distribution rules.

This opens up an interesting possibility... Monsters get killed a lot more frequently than heroes. So... what if you decided to switch teams, just for your own benefit? Casting debuffs on your allies and buffs on the heroes, or maybe debuffs on both just to be sure? Of course, that doesn't seem very... nice. Do you really want to stab your fellow monsters in the back like that?