It depends,but why is Ronald in danger of imminent death? Rika and Satoko actually don't present that much of a threat unless Shion, Rena or Keichi are related (Maybe in Satoko's case its possible, Rika has Akasaka and both of them have Rena on their side), but if you're talking about Satoko and Rika with none of their friends related they're pretty much screwed, another bad end.
Granola said: rika has shown she is fully capable of violence.
although she gets her ass kicked every time.
satoko COULD throw up on him.
Yes, she can turn violent from time to time clearly shown in Saikoroshi-hen, still she has the body of a child and its not capable of much, and also remember we're talking about Japanese-Ronald which is some kind of abomination/anomaly that should never have existed.