The Daughters of Temperance Hobbs question

Spoiler alert: This is regarding Connie’s familiar, Arlo, the dog-like creature.

Several times, the author describes how familiars are able to disappear and re-materialize at will. So it makes absolutely no sense that after Arlo alerted Sam to the fire, he didn’t just de-materialize and appear somewhere outside the apartment. If Arlo chose to die in the fire, the author should have made that clear. It really bugged me, especially since at the end of the book the familiars of Connie’s daughters appeared. I know that prior to that, the point was made that familiars could come back in other forms and I got that the author was insinuating that these familiars were Arlo in new forms. I guess I wasn’t satisfied if how that plot point was handled.