The Tesla MID is in the Tesla Gateway or Backup Switch meter socket adapter. The Pila MID is onboard inside the battery. Pila can push power back through the plug.

When utility power drops, Pila & Powerwall react exactly the same. They both detect the outage, open the MID, and power load downstream of the MID. In the case of Pila it powers loads downstream / plugged into Pila.

Im having trouble understanding this, if you back feed into a circuit why wouldn't it go out via the beaker and onto the power grid?