Disappearing in middle of a 1v1

Hello, today in a world pvp I had 2-3 fights with a paladin around K3. When he saw that he is loosing he is disappearing into the middle of the fight and appearing again around the same place he disappeared but with full hp in 2-5 seconds and he can do it 3-4-5 times in a row. Because his health was full I must say that this is not lay of hands, it happen a few times for 2-3 minutes.
My question is : How is this possible, if I press Alt + F4 in the middle of the fight, after I login again my character is death. I’ve tested it.
I want to ask how the server can prevent this, I don’t think that this is correct behavior. I’ve seen it also in other world pvps and in a lot of YouTube videos about pvp at Warmane Icecrown.


Can also someone explain better how this is happening, please without comments like Alt + f4, feign death + … and other bull****s, it's visible that this shouldn't be allowed.

Thanks.

If he is out of combat, some1(friends / alts) can summon him to dungeon or if it was rdf, he can reenter, or rbg

i would guess it could also be done by using something called "Disconnect script", a thing in the past that is many times since fixed but perhaps such one still exists.. it supposedly instantly disconnects you no questions asked, no matter what's happening

this sounds like phasing, players get phased in certain areas depending on certain quests being done.