I don't think there's much of a worry tbh - Roman won't be even the slightest bit interested in keeping him on.
Compared to the other guys who've "stepped in" whenever Roman's fired someone (Hiddink, RDM, even Grant)....Benitez is not exactly going to be a resounding success is he?
Having said that, Benitez was in a much weaker position than those guys, in terms of the tools he has at his disposal. I've written a little something about it, if anybody fancies a butchers! http://twobanksoffour.wordpress.com/2013/01/28/abramovichs-gamble-set-to-backfire-for-once/