HICKSVILLE - ? A retired NYC firefighter who nearly died on 9/11 organized a memorial yesterday. Bobby Senn helped build 12-foot replicas of the Twin Towers on his front lawn. The towers were the backdrop of a ceremony that was held in Hicksville. The retired firefighter had to crawl out of the rubble up to his armpits when the South Tower collapsed. Senn suffered broken bones and burns, but lived to tell his tale of survival.