I know I'm too late but I think the scenario is written almost perfectly. The actors and actresses captured the emotions in a very affective way. The only issue is, they could've detected Mark White much easier if Ivy went up with the "flirting act" on the phone, instead of directly asking questions about Phoebe(?), risking Ivy's life by sending her to the meeting. Asking questions directly like that isn't really smart and as detectives and polices, they should've known about it.
To be honest, for a moment, I really thought Ivy was REALLY lying and trying to protect Mark White because of her mysterious and passive aggressive behaviour. Which makes me question whether the show did a really good job on making you keep up with the scenario as if you're witnessing the same situation or I'm just easily fooled by assumptions.
Overall, I really liked it, the way it ended was actually great. She was back to her family, as she always has wished. Instead of finishing the series with action, they finished it with calmness.