This is one of the endings of the 'Extended' episode.
*** Spoiler - click to reveal ***At the end, while you have your injured friend, put them in the machine that looks like the one that fixed you earlier. Use yourself to complete the circuit by hovering within the broken wire to the right. This will kill yourself, but save your friend, you noble little robot you.
To get the other ending (and other trophy), from the main menu just hit Extended, then continue and do the actions described in the other trophy: