Is this a 2KO?

[Flashley_ska]

Playing a khans draft last night, I had my opponent on the ropes, but was one point of damage short of killing him.
I pull {Lightning Shrieker} put it into play and go all in.
He then interrupts before damage to play  {Deflecting Palm}, choosing the shrieker as his source... And I have 5 life.
Thanks to  {Vaultbreaker} I get to chuck a land and draw defiant strike, getting me that +1 I needed in the first place, leaving both of is simultaneously on 0 life, hence... draw?

Is this correct or should there have been an order to the damage resolution and state checks?

[Splicer]

No, what happens goes like this:
1. You attack with shrieked and vaultbreaker, drawing the strike
2. Either you cast strike first or he casts palm first, the order dosen't change the chain of events
3. They resolve. If you give your shrieker +1 before Palm resolves, you take 6 and lose. If you resolve it after palm, you lose. If you give vaultbreaker +1, Palm still kills you. The spells resolve before the damage step.

[Flashley_ska]

(Another attacking creature got the +1, and it was after he cast his palm, incidentally)
But Palm resolves before damage is dealt, and puts a delayed ability, that fires when damage is dealt, so how does that work?
The spell isn't strictly doing the damage, the ability it leaves behind is?

[Splicer]

Ok, then it depends on the order in which damage was delivered.(deflecting Palm does do the damage, by the way). In any case, one of you had to die first, this would not end in a draw.

[Kaylesh]

Playing a khans draft last night, I had my opponent on the ropes, but was one point of damage short of killing him.
I pull {Lightning Shrieker} put it into play and go all in.
He then interrupts before damage to play  {Deflecting Palm}, choosing the shrieker as his source... And I have 5 life.
Thanks to  {Vaultbreaker} I get to chuck a land and draw defiant strike, getting me that +1 I needed in the first place, leaving both of is simultaneously on 0 life, hence... draw?

Is this correct or should there have been an order to the damage resolution and state checks?

So, spells resolve. Next time Shrieker does damage, it doesn't, but you get the damage. You still get the three damage needed to kill him out of {vaultbreaker}. So all damage is done in the damage step. I'm in doubt right now, gonna double check.

Edit: http://imtgapp.com/forum/index.php?topic=41750.msg417423 has got some more discussion on this.
Thing is, palm creates a replacement effect for the next time a source would deal damage, so damage is dealt simultaneously. Aka draw.

[Oldschoolmtgnoob]

I may have missed something, but did you do {vaultbreaker}'s ability after he did Palm? Because I don't think you can do it if you've passed priority to another player, which is assumed, being that he cast a spell. I think you'd have to do it as you declare him as an attacker. Could be wrong

[particle]

{deflecting palm} will not do any damage until the combat damage step. The same time all the other combat damage is done. Palm is a replacement effect that applies at the point that it is preventing the damage. So assuming your opponent is taking lethal for non palmed damage and you are taking lethal from palmed damaged, the game will end in a draw.
Note that if this is game three in a sanctioned tournament you will have to go to game 4 (time permitting). This is because it's the first to two wins. You can only actually have a match end 1-1-1 if you go to time or intentionally draw.

[particle]

wouldn't giving vaultbreaker first strike kill the opponent before the palm stops the dragon from dealing damage and then in turn deflecting it to the players face?

first strike vault breaker kills opponent before dragon goes nom nom on your own face?

What's giving first strike? Not {defiant strike}.

[Splicer]

Dosen't the attacking player choose in what order damage is dealt? If this is the case, you could kill him before the effect kicked in.

[Remillo]

Dosen't the attacking player choose in what order damage is dealt? If this is the case, you could kill him before the effect kicked in.

Only when multiple blockers are involved.  All damage is dealt at the same time, regardless.

[Splicer]

Dosen't the attacking player choose in what order damage is dealt? If this is the case, you could kill him before the effect kicked in.

Only when multiple blockers are involved.  All damage is dealt at the same time, regardless.

So it is a draw? That's cool. You learn something new every day.

[particle]

Dosen't the attacking player choose in what order damage is dealt? If this is the case, you could kill him before the effect kicked in.

Only when multiple blockers are involved.  All damage is dealt at the same time, regardless.

So it is a draw? That's cool. You learn something new every day.

Yes it's a draw. Palm will deal damage at the same time as your other creatures. The game will see both players at 0 and the game will end as a draw.

[LinkCelestrial]

I remember an old ruling here saying {Deflecting Palm} wins...imma try to dig it up.

Found it and bumped.

[Splicer]

This is the ruling from link's bump

As a point of correction, Deflecting Palm does not create a delayed trigger, since that implies something totally different.  Triggers always have the words 'When', 'Whenever' or 'At' at the beginning of them.  What Palm does, however, is set up a replacement effect that will simply apply the next time the stated event happen and replaces that event. 
The way this works in combat with ties, to answer one of the OP's questions:
Both players are at 5 life.
Player A attacks with two 5/5 creatures.
Player B, with no creatures, doesn't block, but casts Deflecting Palm and chooses one of the 5/5s
Damage happens, as modified by Palm, causing a 5/5 to hit Player B, the damage from the other 5/5 being prevented, and Deflecting Palm to deal 5 damage to player A.  This ALL happens before State-based Actions are checked.
Both players are at 0 life, and both players lose due to state-based actions.

It is indeed a tie.

[Flashley_ska]

Thanks all, we went with the tie at the time but as it's so rare it seemed like maybe we were missing something. It's nice to have confirmation!