I imagine they left it open on purpose to allow Melissa Navia, who had a pretty rough year during production of season 2, an opportunity to be written out of the story.
I would love for her to continue though, because I like her way more than Tom Paris, too.
As this week’s episode was pretty grim again, I’ve added detailed content warnings to Does The Dog Die at https://www.doesthedogdie.com/media/896237?index1=2&index2=8. Warning: Some of these can be a bit spoiler-y, but people who read DTDD usually value detailed CWs higher than not seeing any spoilers whatsoever.