The warning arrives at the moment it can do the most damage — Sam already bonded to Lou, already caring about the BB in ways that the Bridges mission did not anticipate and does not have a protocol for. The procedure that may erase Lou's memories is the disconnection Sam has been avoiding thinking about, the end of the relationship that was supposed to be operational rather than personal. Lou is cargo. Lou is a tool. Lou is the person Sam has been talking to across every lonely stretch of road.

Deadman warns because he can see what Sam cannot see — that the attachment has become the kind of attachment that costs something when it ends, that the professional relationship has become the personal one, that the mission's completion will require Sam to do something to Lou that the Sam who started carrying him would not have anticipated needing to do.