Eichi's in no state to be trying to wrestle away someone's weapon, and once again Keito is overtaken by a thought like, Even I could fight him off without trouble. So Keito doesn't let himself be troubled by Eichi glancing at his weapon, even though Keito knows that Eichi wouldn't hesitate to kill him.

So why is he so relieved that Eichi remembers him, too?

"That's right." He doens't think about it, making himself focus on the subject at hand. Like why he didn't just blow Eichi up and leave, which definitely isn't just because he's too soft to kill a downed enemy. "You may have lost the fight, but you still damaged my ship. I need yours to repair mine." Everything is entirely practical over here, yes sir. And... he'll leave it at that. No need to hint at how important his own scouting mission was, and how suspicious it is that Eichi was sent to the same place on the same day.