So my wife and I had a very close game just the other night. We finished our 3rd Mystery during our Encounter Phase but wouldn't be "Solved" till the end of the Mythos Phase.

The Doom track was on 3, we drew our last Mythos card and the Mythos card had us move the Omen Tracker. The now current Omen matched 3 gates we had on the board which forced Doom to 0. Azathoth awakes and Investigators lose the game.

My wife and I accept our defeat.

Then I got to thinking. In the rule book it says if the investigators lose and win at the same time then they win. Would this be considered one of those instances? I know I am probably grasping at straws here because Azathoth's Flip affect resolves before solved Mysteries are resolved at the end of the Mythos Phase. But because the Investigators Both Lost and Won in the Mythos Phase does it count as a win? Or is it one of those which ever happens first moments?

Whatever happens first I think.

I don't think they happened at the same time ... Azathoth work first so you lost.

A case where you might have simultaneous would be having your last investigator reduced to 0 health while at the same time defeating the Cthulhu epic monster (= final mystery for Cthulhu). In this case you would win since the rules say to deal damage to investigator and monster at the same time.

Yup. Another case I can think of "simultaneously" is when there are no Mythos in the deck and the investigators solve the last mystery: the next Mythos to be drawn would cause the Mythos Phase to end and the game to be lost, but in the same Mythos phase investigator would also win, so that you can choose what effect to be triggered first

Julia, I'd interpreted that situation as the first thing you do during a Mythos phase is draw a card which causes you to lose. You aren't at the end of the phase yet so the game ends before the mystery is solved.

I must say I like your interpretation better as it removes the frustrating last turn where there is no possibility of winning.

Julia, I'd interpreted that situation as the first thing you do during a Mythos phase is draw a card which causes you to lose. You aren't at the end of the phase yet so the game ends before the mystery is solved.

I must say I like your interpretation better as it removes the frustrating last turn where there is no possibility of winning.

Yes, that was my first reading too, but then I stand corrected. Additionally, if the last turn wasn't good to win the game, rules would have been worded like "when the last Mythos card of the deck is resolved, the game ends", while the reference guide states: "if a Mythos card cannot be drawn, the Mythos Phase ends and investigators lose the game". I believe the key word here is "Mythos Phase ends": if it ends, hence it begins and immediately ends. And when it ends, two things happen at the same time: you lose the game, and you win the game by completing the third mystery.