What led Yehuda to confront Joseph when all the brothers shirked away?
One explanation I really liked is from Meshech Chochmah. At the end of Mikeitz, Yehuda realizes that Joseph's punishment for Benjamin is a result of a fabricated charge. Benjamin had just been branded a thief after being caught 'red handed' with Joseph's goblet. Why then does Joseph want a thief to be a servant in his own household? Yehuda realized that this was a forced predicament (as Sforno remarks in VaYigash 44:18), and this gave him the courage to approach Joseph and contest the punishment.