The suit walks up the mech like Inspector Gadget with suction cup feet, gets in place, turns about to be "facing" down, then bends the BA's "knees" so it is facing forward looking in the same direction as the mech (if on a LT/RT)
Though I admit this might be awkward at first and take some training to get used to, I imagine a lot of things in BA training are like that. How they manage it in 15 seconds is more interesting