The missions is a one way circle, so time saves came from being more efficient. First was the 2 shot quick kill on Tatoo. A small amount of time could still be saved by not landing next to him, but the farther away the more likely he is to heal before the second shot gets him. The climb up the second building has also been better optimized, using breaching charge to save ~1 second on each of the late Machette spawns and using sniper support to skip the wait on the 3rd floor entirely.