My kingdom for us getting an Eddie begins parallel of the FaceTime calls between Eddie and Shannon and Chris in disconnected.
Only this time Eddie is in Shannon’s place - and Buck answers FaceTimes/called Eddie from the firehouse - but he keeps having to hang up because the alarms go off - so they don’t get to talk for a bit - and Eddie gets frustrated by it - and realises how Shannon must’ve felt - and that leads him to connecting the dots about why he’s placing himself and Buck in the same scenario and him and Shannon - but knowing he can do something about it and go back to LA - that there is nothing keeping him from being with Buck except himself - and so that’s how he ends up moving back to LA with Chris!!