The final moments of The 2nd Runner. After stopping Aumaan from destroying the Solar System, Dingo and Leo return to Ken (on board the fake Anubis) from Phobos' explosion with their mechs completely wrecked. Dingo and Ken immediately rushes and embraced each other with their frames. In the anime cutscene that follows, Ken cries into Dingo's chest after he affirms his trust in her.
ADA and Leo bonding in the second half of the first game, especially during their trip to the Central Hub. From Leo telling ADA a story of his childhood as a means of explaining his reasons for continuing to pilot Jehuty and fight against BAHRAM in spite of his repeated stated reluctance to do so; to Ada telling Leo not to be careless in action as not only does she need him, but she does not want him to die. Leo expresses nothing but lament and sadness when he learns that Jehuty is to self-destruct as part of its mission to Mars, destroying ADA as well. The two had really come far in their friendship since the beginning of the game.
The second game took this even further. Leo was willing to go against orders to protect Jehuty and ADA; and ADA remembered a lot of Leo's words, like suggesting the enemy-halting Geyser on the UNSF LEVs when Dingo wanted to save the civilians.
Leo's actions before and during the second game: Taking a Level in Badass, attacking Dingo on Mars, jumping Anubis the second he makes it into the base, and even trying to hurl the battered Vic Viper into Aumaan's reactor, are all done for one reason: Leo is trying to take the burden off A.D.A.'s shoulders.
YMMV on this one, but seeing the Fake!Anubis embrace the wrecked Jehuty after Aumaan is destroyed is oddly heartwarming in a way. Like a reconciliation between the two brothers.
Considering that Ken was piloting it at the time, it works two ways.