i think you created an image of Liz to be some angelic figure,
She's not, she human, and above all else she's a businesswoman, I think she did good with how she handled stella, stella just tried to screw her over and blame liz for the failure of the task, while the PM does take ultimate responsibility in most tasks this was pretty much an individual task. And stella and laura's team messed up big time. What was Liz supposed to do over the phone.. Stella and Laura made a huge mess up of the task, bewing unwilling to haggle, undermining Laura in negotiations, not being personable and being too corporate in her interactions, if Stella came into my store, I would see a massive ££ sign over her head, and would sell to her for as much as I can. I sell computers, mainly online through my web store. I do get the occasional local buyer driving to my warehouse to collect and avoid p&p fees.
If stell came to me I would sell at RRP + try and upsell some extended warranty, insurance and accessories with it.
If Stuart and Chris came to my store I would probably have a laugh, give them a discount, and let them go off their way.
Having a personality, being likable is very important, I think jamie's technique of "having a story" was absolutely genius and it worked very well for them, even though Jame messup up in the task, incurred £150 worth of fines, and RRP costs, his strategy was sound.
It's not often that you get to be personable with a buyer, their approach of these ridiculously made up stories was a great way to connect with them, and allowed the retailers to be generous with the discounts.
Stella was too corporate, and IMO Stella has no chance of winning, I have my doubts about Laura, she failed as PM [she even reminded Alan of it in the boardroom, lol], she came back with £0 order book, but she's only 22, and I think she's more of a entreprenuer than Stella.
So.. to sum up, it was all Stella's fault, Liz did everything she could do, Stella had no business pointing the finger at Liz, Stella should have taken joint responsibility with Laura.
Liz needed to do what she did in order to make a point, so that Stella did not cross her again. and she made the point very well.