A rescue device includes a pulley includes a support flange with two rotation shafts mounted salient and extending in a first direction. Two sheaves are mounted rotatable around two rotation shafts to define a running line of a cable. Two flanges are mounted rotatable between a first position and a second position. A first blocker is configured to present a first position blocking the first flange in the closed position and a second position allowing rotation of the first flange. A second blocker is configured to present a first position blocking the second flange in the closed position and a second position allowing rotation of the second flange. The second blocker is independent from the first blocker.