In Part 4 of Black Lagoon: Roberta's Blood Trail, Shenhua attacks Roberta and is swiftly backed up by Sawyer and Rotton. Roberta breaks Sawyer's chainsaw and one of Shenhua's kukris, has the two held at gunpoint... then just kicks Rotton in the balls and walks away, sparing all three of them.
I haven't watched Part 5 yet, but so far this is the only time Roberta has shown mercy in the entire OVA. Later on in Part 4, she reacts to Eda helping her by promising to kill her painlessly, yet here she spares three random strangers who were trying to kill her, two-thirds of whom were still armed in some capacity. I don't understand why.
It could be that Roberta's just trying to catch up to the American soldiers and/or Garcia, and doesn't want to waste time killing them, but she doesn't seem to be in that much of a hurry - as I noted, she walks away from the incident in question. It could also just be that she's gone completely insane at this point, and trying to analyse her actions is a waste of time. But I'd like to try anyway.
Why didn't Roberta kill Shenhua, Sawyer, and Rotton?
To repeat: I haven't seen Part 5 yet, so I don't want to Google anything in case I stumble across any spoilers. If the answer is "watch Part 5", so be it.
