Ok, let me see if I can help 'shed some light' on this here....lol.
Scenario:
P2 has a set "
Wall of Revealing Light", a set "
Last Turn" and a face-up "
Jowgen the Spiritualist" on the field.
P1 has 2 cards in hand and a face-down "
Sangan" on the field.
P1 draws for their turn.
In response to the Draw, P2 activates "
Wall of Revealing Light" (paying the cost to lower themselves to 1000 or lower).
P1 does not respond.
P2 then chains "
Last Turn".
P1 does not respond.
P2 does not respond.
P2 chooses "
Jowgen the Spiritualist" to remain on the field.
All other cards are sent to the Graveyard.
This ENDS the resolution of "
Last Turn" and the lingering effect will begin as soon as all other effects have finished resolving.
"
Sangan"s effect will resolve now BEFORE P1 would attempt to Special Summon a monster.
P1 chooses "
Magician of Faith" and adds it to their hand.
NOW the lingering effect of "
Last Turn" will resolve. Keep in mind, all of this is happening during the DRAW PHASE of P1.
P1 cannot Special Summon, and as such, there will not be a Special Battle Phase.
NOW the lingering effect of "
Last Turn" is resolved. The only thing left for "
Last Turn" to do is it's victory check at the End Phase of P1s turn. But we're still in the Draw Phase.
So, we complete the turn as normal.
Standby Phase, neither player has anything to do, so we move on.
Main Phase 1, P1 summons "
Magician of Faith".
Neither player responds, so we move on.
Battle Phase, P1 attacks and destroys P2s "
Jowgen the Spiritualist". P2 takes 100 points damage.
Main Phase 2 (if needed), neither player has anything to do.
End Phase, "
Last Turn" will now perform the victory check.
Guess what...P1 will win since they are the ones left with a monster on the field.
BTW...this is all spelled out fairly clearly in the rulings for "
Last Turn". All you have to do is click on "
Last Turn" pretty much anywhere in this thread to read them...lol.