Declare Lightning Runner as an attacker, triggering its ability.
Holding priority, activate Circle of Dreams Druid by tapping it, adding at least six .
Activate Emiel by paying 3, blinking Reservoir Walker.
Reservoir Walker enters the battlefield, causing you to get EEE and gain three life.
Repeat from step 3 one additional time.
Resolve the Lightning Runner ability from step 1, causing you to get EE, then pay eight E to untap all creatures you control, and to get an additional combat phase after this one.