i'm also just thinking of her in a murdergame. because i think at first while she would refuse to participate out of spite and state very loudly her intent to kill the mastermind, she would still be having a ball before someone she got attached to ended up dead.
also yeah she's okay with killing but she has scruples. 1. she has to think the person in question sucks 2. it's her own choice to kill and she's not being forced by some amateur jigsaw making threats against the things she cares about 3. it won't put the people she likes/considers hers (literally just her family, eugene and enid in the show) in danger.
she writes an essay of complaints on everything ineffective about the mastermind's set up and talks about how if she were to run a murder game she would do it so much better
like she'd make no attempt to hide the fact that she's an assassin and has killed people but she very much would not do it for whatever the fuck the mastermind has going on
i had a character who had a kill count of several thousand and had absolutely no moral issue with killing but he didn't want to kill because he knew he wouldn't get away with it and he wanted to be around to look after the teenagers he'd adopted.