These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Les Yay: It is more or less universally accepted that Theo had a crush of some sort with Nell. A lot of the things she says to Nell come as very flirty, and a lot of her actions can only be explained as her being jealous of Nell and Dr. Markway becoming closer. Not to mention, her making fun of Nell also comes as some manner of teasing.