Ф-30

ПРОЙТИ (ВЫЙТИ, ПРОСКОЧИТЬ) ФУКСОМ obs, coll VP subj: usu. human or concr) to make it through (some test, bureaucratic process etc) by chance

by some (lucky) fluke.

Хоть десяток отказов! Пиши дальше! И в конце концов, по закону больших чисел, пропуск твой проскочит фуксом через бюрократическую машину (Гинзбург 2). You might have had ten refusals. But never mind, slap in another application! Finally, according to the law of averages, your pass would emerge by some lucky fluke from the bureaucratic machine (2a).