When Body Launderer enters, Blasting Station triggers.
Holding priority, activate Blasting Station by tapping it and sacrificing Sister Hospitaller.
When Sister Hospitaller dies, Body Launderer's first ability triggers, causing Body Launderer to connive.
Resolve the Blasting Station ability from step 3.
Resolve the Blasting Station trigger from step 2, untapping it.
Activate Blasting Station by tapping it and sacrificing Body Launderer.
When Body Launderer dies, its second ability triggers, returning Sister Hospitaller from your graveyard to the battlefield.
When Sister Hospitaller enters, it and Blasting Station trigger.
Resolve the Blasting Station trigger, untapping it.
Resolve the Sister Hospitaller trigger, returning Body Launderer from your graveyard to the battlefield and causing you to gain 4 life.
Repeat steps 2 through 6 one additional time.
Resolve the Blasting Station ability from step 7.
Repeat from step 7.
This clever loop relies on the seamless interplay between resurrection and sacrifice to continuously recycle your threats. When you sacrifice Sister Hospitaller, its loss fuels Body Launderer's connive trigger, while simultaneously setting up the return of Body Launderer itself. Once Blasting Station does its work, Sister Hospitaller enters the battlefield to pull Body Launderer right back out of the graveyard—gaining life along the way and constantly untapping Blasting Station so you can repeat the execution indefinitely.