The cutscene where Superman and Raiden finally decide to team up against Dark Kahn.
Also, the scene just after, when they do beat the crap out of him.
The Enemy Mine situation of the story, where even Shang Tsung and Liu Kang have to willingly join forces. This not only leads to Shang protecting Liu at one point, but then Liu repaying Shang in kind by protecting him from Raiden. This is on top of other scenarios like Sonya having Shang spare her mortal enemy, Kano.