If Vex, Apathetic is on a battlefield and an opponent plays Tideturner to base, does Tideturner get stunned before its move trigger can resolve?

Ruling: It depends on who is the Turn Player. If the Turn Player plays Tideturner, Vex's stun trigger resolves first, stunning Tideturner and preventing it from moving (though the other targeted unit can still move). If the Non-Turn Player plays Tideturner, Tideturner's move trigger resolves first, allowing the swap to complete before the stun is applied.

Sequence:

• When Tideturner is played, both triggers occur simultaneously
• Per turn order rules, the Turn Player places their triggers on the chain first, then the Non-Turn Player
• The chain resolves Last-In, First-Out (LIFO)
• Turn Player plays Tideturner: Turn Player's trigger goes on first, then Vex's trigger on top → Vex resolves first, stunning Tideturner before it can move
• Non-Turn Player plays Tideturner: Turn Player (Vex's controller) places Vex's trigger first, then Non-Turn Player places Tideturner's trigger on top → Tideturner resolves first and completes the swap

Nuances:

• When Tideturner is stunned first, the targeted friendly unit can still move to Tideturner's location due to partial resolution rules, assuming that unit isn't also restricted from moving
• The term "Turn Player" refers to whose turn it is, not to be confused with "Active Player" which refers to the player with focus during a showdown