"desarrollar en los pasillos" se refiere a dar una explicación en los pasillos del congreso de los diputados (el parlamento español). En cuanto al verbo "apuntar" es "dar a entender". Now in English, just in case :) . "desarrollar en los pasillos" means that Calvo (somebody's surname) gave a detailed explanation to the press in the corridors of the Spanish parliament. Regarding "apuntar" it means that something was implied in a conversation, yet not openly said.