Responses
What does it mean??
The MC accepted the ML's gesture, meaning that he ultimately switched sides due to feelings of betrayal (hinted at since the dialogue in the scene right before described MC's unit as a bunch of defects and good for nothings). ML "ignited" the spark of rebellion in the MC via lighter, if you want a very non-subtle interpretation of the scene.
HE TOOK THE LIGHT HE WAS OFFERING HIM AAAAAAH SYMBOLIC YAOIII