Nah nah nah, this is what happens: Upon your first death you lose a total of 25% of your current exp. So if you had 100 you'd lose 25 of that. In a few minutes you respawn at a sanctuary you last visited. You don't get booted off for 24 hours until you end up dying without enough EXP to cover that original 25%: So for example you die a second time. Instead of losing 25% of 75, you just lose another 25%, because your first death you already lost 25%. This means for most, you have about 4 lives to spare before you're booted off, unless you can somehow scrounge up the EXP to spare save yourself. Also the 24 log out only applies to characters at level 3 and above: everyone else can still play even if they have no exp to lose. And no, you don't go into death debt. Maybe...

As for how much EXP you get for killing someone, that is dependent on the NC system, which doesn't have anything to do with how much you lose upon dying. That Rogue only got 6 exp from killing Rocket Lnacer because he was two level lower (This only gets 1/5 of the total amount) and Rocket Lancer was level 3. 30 * (1/5) = 6 exp. Of course Rocket Lancer now loses a 25% of his current EXP, and if he doesn't have any... I hope you have some real life hobbies.