Do Icathian Rain's reflexive triggers create a chain, and can you retreat a unit in response to save it from the targeted damage?

Ruling: When Icathian Rain resolves, all 6 reflexive triggers are added to the chain and must select their targets at that time. If you retreat in response to the initial Rain before it resolves, the opponent can retarget when triggers are added. If you retreat after the triggers are on the chain, the targets are already locked in and retreating will cause those triggers targeting the retreated unit to do nothing.

Sequence:

• Icathian Rain is played and goes on the chain
• If Rain resolves, all 6 reflexive triggers are added to the (now empty) chain
• All 6 triggers must select targets when added to the chain
• You can respond to any trigger on the chain with retreat
• Triggers targeting the retreated unit will do nothing

Nuances:

• If you retreat in response to the initial Rain (before it resolves), targets are not yet locked in and the opponent can choose different targets when the reflexive triggers are added
• Once the reflexive triggers are on the chain with targets selected, retreating will only save units from triggers already targeting them