“As the Doctor prepares to follow, Ace asks his permission to stay behind with Robin, but the Doctor asks her to take one more trip with him first… (blah blah, other plot points are explained)….and the Doctor and Ace watch with satisfaction as the star collapses into a black hole, trapping the Sentience forever. Ace now expects to be taken back to Crook Marsham, but the Doctor has another agenda for her, and instead he vanishes into the TARDIS corridors, refusing to acknowledge her pleas to be taken back.”

-wiki summary of “NightShade” or that time Seven convinced Ace he was gonna leave her on Earth with the current “love of her life” but only tricked her and then hid in the TARDIS so she couldn’t beat him up. Basically, the best description of Seven.