In Part 1 we have the Master telling Graham about his shelf of Doctor stuff and asking if he wants a look. Graham looks like he’s thinking about it.
Later Yaz appears in the box, in the Master’s TARDIS (still waiting on an explanation as to why she was spat out there in particular but never mind).
Replace the time taken for scene with Ryan’s comforting because while I certainly like a bit of Ryan/Yaz cuteness I need the time, and it makes her look disproportionately traumatised vs. how she will act for Part 2.
In this version, give Graham the chance to comfort Yaz, nursing some not-iced tea, while the Doctor goes off to get Ryan and will ‘just be five minutes - unless we stop for donuts, would anyone like donuts?’, and the concept of the shelf is brought up by Graham to Yaz. The camera pans up ‘behind’ the shelf, the two characters gaze on it, with the Master behind them. With some Australian snake imagery around for when you rewatch this scene.
Then at the end of Part 2, when the Doctor does her bit of opening the floor for questions, have Ryan be the only one who’s asking questions, curious by nature as he is, and the other two, subtly not quite looking at her, until she does her Tenth Doctor Script, in surprise that she’s said anything at all.
Benefit: Tension between characters, the question of did they or didn’t they look at the shelf, altering the character’s ‘good companion’ standings, allowing for some juicy Master as genesis serpent imagery/meta should you want that in the future (and as he’s got secret knowledge about the beginning of the Time Lord race it looks like you do), and the audience is left wondering how much they know - allowing you to pull some Chekov’s Information at some point in the future.