Add to that the fact that the best case scenario post-election for Kaye just got a lot less attractive in the past few days.
Last week, her best case was that she could be Deputy Prime Minister.
This week, her best case was that she would be Education Minister. Been there, done that. She was Education Minister under Bill English.
And then there's the fight to win back her Auckland Central seat.
And it would've been a fight.
Her margin on that seat's always been slim - 600, 700, 1500 votes - even when the Nats were in government.
If you factor in this year's swing towards the Labour Party, it might've brought that margin down and made the fight a lot harder.
Kaye's resignation is not a good look for Collins.
Kaye's been arguably the most prominent urban liberal in the party. She's been very important to balancing out some of the really old-fashioned socially-conservative thinking in there.
She's young, she's beaten Jacinda Ardern twice, and she's done a good job of the portfolios she held as a minister.
It never looks good to have MPs quitting immediately after a leadership change – especially two in one day.
But I'm not sure this is Collins' problem. It feels more like the leftovers of a Muller problem, that Collins is having to deal with.
* Heather Du Plessis-Allan hosts Drive on Newstalk ZB, weekdays 4-7pm.