why. (Sprint code)

global int 0:S7_SS_OldSpeed [];
global int 1:S7_SS_Sprinting [];

script "S7_SprintSystem" ENTER {
    if (gameType () == game_Title_Map)
        terminate;

    int tics = 0;
    while (TRUE) {
        if (checkWeapon ("S7_SprintWeapon") && S7_SS_Sprinting [PLN] == 0) {
            setActorProperty (0, APROP_SPEED, S7_SS_OldSpeed [PLN]);
            S7_SS_Sprinting [PLN] = 0;
            tics = 0;
            disableWeapon ("S7_SprintWeapon", "S7_Sprinting");
        }
        if (keyDown (BT_USER1) &&
            S7_SS_Sprinting [PLN] == 0 &&
            checkInventory ("S7_Stamina") >= 5 && !CheckInventory ("S7_Dying") &&
            !S7_SR_StaminaEmpty [PLN]
            ) {
            S7_SS_Sprinting [PLN] = 1;
            S7_SS_OldSpeed [PLN] = getActorProperty (0, APROP_SPEED);
            disableWeapon ("S7_SprintWeapon", "S7_Sprinting");
        }
        if (keyUp (BT_USER1) && S7_SS_Sprinting [PLN] && !S7_SR_StaminaEmpty [PLN]) {
            setActorProperty (0, APROP_SPEED, S7_SS_OldSpeed [PLN]);
            S7_SS_Sprinting [PLN] = 0;
            tics = 0;
            disableWeapon ("S7_SprintWeapon", "S7_Sprinting");
        }
        if (checkInventory ("S7_Sprinting") && S7_SS_Sprinting [PLN]) {
            if (checkInventory ("S7_Stamina") >= 5) {
                if (checkInventory ("S7_Sprinting") && tics >= 5) {
                    tics = 0;
                    if (getVelocity () > 0)
                        takeInventory ("S7_Stamina", 5);
                }
                if (checkInventory ("S7_Stamina") < 5 || CheckInventory ("S7_Dying")) {
                    setActorProperty (0, APROP_SPEED, S7_SS_OldSpeed [PLN]);
                    S7_SS_Sprinting [PLN] = 0;
                    S7_SR_StaminaEmpty [PLN] = 1;
                    disableWeapon ("S7_SprintWeapon", "S7_Sprinting");
                    restart;
                }
                if (checkInventory ("S7_Sprinting") && ((abs (getPlayerInput (-1, INPUT_FORWARDMOVE)) > 6400) || (abs (getPlayerInput (-1, INPUT_SIDEMOVE)) > 6400)))
                    setActorProperty (0, APROP_SPEED, 3.0);
                else if (checkInventory ("S7_Sprinting") && !((abs (getPlayerInput (-1, INPUT_FORWARDMOVE)) > 6400) || (abs (getPlayerInput (-1, INPUT_SIDEMOVE)) > 6400)))
                    setActorProperty (0, APROP_SPEED, 6.0);
                else if (!checkInventory ("S7_Sprinting"))
                    setActorProperty (0, APROP_SPEED, S7_SS_OldSpeed [PLN]);
            }
        }

        delay (1);

        if (S7_SS_Sprinting [PLN])
            tics++;
    }
}