I like how those characters behave half-rationally. Noah's reaction is to tell Oliver he fucked up and needs to take responsibility, and consider sending Himeka back. Then twenty seconds later, thanks to heart sleep deprivation induced short temper, she... tries to drown her to shut her up.
And Himeka genuinely feels as someone who is lost, and doesn't take shit when people are looking down on her for things they are themselves to blame for. But she's also seeing the opportunity and trying to turn the situation to her advantage to escape her shitty life.
It sounds inconsistent, and in some ways it is, but each action also makes sense considering the general situation they're in. It makes them feel very human, not just props filling for a specific role.
Himeka's faces and utter disregard for Noah's position and the potential danger she's in, because she doesn't want to bow her head anymore even when it's the "smart" thing to do, are delightful.