Knuckles having the balls to try and punch the monster that was his friend.
In the game, he just runs over to Sonic.
Eggman trying to hide his fear counts too.
Oh yes, KNUCKLES. He was willing to actually try and FIGHT something that was clearly far stronger than him.
In Version 5, after you beat the game, Sonic, learning of Sonic.exe, and the fact that he killed his friends, walks through the demon's dimension, trying to eradicate the damned hellspawn. He eventually confronts him, and the credits roll before the battle.