Found a blind spot higher up the jeep boss which enables a 1-M kill. To make that work I switched to the safer Hovercraft position which is also turning out quicker. Saves me buying an M in 4 shop too. Have been on 13:23-6 pace many times recently, 14 hits from bad RNG cost a few secs, it's just one or two runs until the mid 13:20s and the end of the adventure.