Just because a few nuclear missiles get launched doesn’t mean everybody’s paying attention. The ABC-TV submarine-based drama “Last Resort” premiered Thursday to “OK” or “soft” ratings, depending on which Hollywood-industry website you’re reading, drawing a 2.2 rating and a 7 share in the coveted 18-49 demographic. That put the premiere third in its time slot, below CBS comedy “The Big Bang Theory” and FOX talent show “The X Factor,” according to final ratings released Friday. Finishing below a top-rated sitcom and a Simon Cowell-judged karaoke contest may not sound all that bad, but the “Last Resort” numbers are just slightly…