Richard caught the tail end of the scene and as much as he wanted to go help help he stood his ground. There could be more and he needed to be alert to that. Bringing his rifle up he scanned through the trees while holding his position. It was easy to sense the sudden tensing of the civilians. Even as exhausted as the group was they weren't blind to what was happening. 

[hr]

Rin calmly gripped Marcus's wrist of the hand that held the gun to the young man's head. Though she was winded her demeanor was calm. "Not here, not like this." She said sternly. She was conflicted about whether or not to kill him. He was the enemy, he attacked her with the obvious intention of killing her... But as she listened to his horrified begging and saw the tears stream down his face she was forced to remember he was human just like them. UKD soldiers were rarely recruited voluntary, many having been picked out and trained since they were young teenagers. This boy could likely be doing this just to stay alive, not actually believing in the cause he fights for. No one but him could know for sure one way or the other though. Simply put he was a risk to them if left alive.

Regardless of her own feelings or views she was aware enough to realize they had audience of scared and traumatized civilians, not to mention Tess. These people weren't as cold and hard as her and Marcus, but that wasn't necessarily a bad thing. Executing a young man in front of them all wouldn't help their situation.