Because of Charles's last-minute instructions, the three people lying in wait were all utterly confused; they simply couldn't understand what was going on no matter how hard they tried.
Actually, Charles was just as confused.
When Menilman moved to kill the young girl Zimmerman, he knew something was definitely off, so he cast aside all considerations, reverted to his human identity, pushed the Quickness Technique to its limits, but not to stop his senior sister from killing the young girl Zimmerman.
He figured that once this girl died, there would certainly be some strange changes, and he needed to step in to save someone—save senior sister Menilman!
Although Menilman was privy to some secrets, she couldn't understand why Charles would react so quickly, coming to her aid the moment she made her move, protecting her...