Based on what I know, by default, it works like this:
While the MVP has HP > 0, the player who deals more dmg until the MVP dies, win. You can log off in the middle too but if you do log on, be sure to move in the 5 seconds of grace time before it dies or you will lose the MVP because the server still recognizes you "as off" during that time. You can die, come back, relog, whatever you want but you've to give 50+% of the total dmg done on the mvp and not be on the grace phase to be considered MVP.
Small example:
2 people fighting for an MVP that heals a lot.
MVP has 20kk HP.
With the heals, there is a pool of 30kk HP to fight for during the competition due to constant heal of the MVP.
The winner is the one who gave more then 15kk total dmg.
There are still some weird occasions where some weird stuff happens due how dmg is done and calculated by the server tho:
- Your give dmg, the mvp too. Your comes faster then the one given by mvp but you would die if you had taken and you saw the dmg pop up in game. If you're dealing with @autoloot, drops may appear on the floor but you will be alive because you would be dead if the dmg would hit you.
- You give dmg, you die along with mvp. If what killed you was reflect dmg and the mvp didn't give any dmg back during that time frame, you will get mvp and the drops if dealing with @autoloot. Nothing will be dropped on the floor.