Bob Rae saw the writing on the wall that the Liberal Party back-room boys would rather have no leader than ever have him as their permanent one so he is “offering” his services as interim leader (see here).
Rae also knows that being a regular member of the 3rd party in Parliament would really suck for a guy with a socialist silver spoon stuck in his mouth and a massively over-sized ego. At least as interim leader there are some nice living and pay perks not to mention the friendly media always calling for comment and interviews. Rae’s little game of pretending to do the Liberal Party a favour is only another way for him to pamper himself.
If there is no way for him to take over the Liberals once a leadership race time-frame is established, watch for him to resign “for family reasons” taking his public pension with him to a cushy corporate or university gig.