GTA VCS. Obtaining a FP/EP Benson - mission pass method | Farewell to arms

Fast memory off

When you get to Diaz's mansion and rampage fails, you need to skip the cutscenes by the certain way, otherwise you may not be able to shoot during the mission.
1) Wait or skip the 1st cutscene (2:44-2:47)
2) When the game says "mission failed", start the mission again and don't skip the 1st cutscene this time (2:49-2:53)
3) After that skip all the cutscenes

When Gonzalez enters the airport, turn the aim right after skipping the cutscene to make an enemy car spawn on the left side (5:05). This will decrease a chance of softlock.

Also you may lose your heavy weapon after these actions (flame thrower, m249, minigun or RPG).

If you dupe the mission as usual, it will most likely softlock when you get to the airport. That method is highly luck based, and the one shown in this video has only a low chance of softlock.