I only watched a bit. I think Starmer is trying not to be rude and was waiting his turn, I think Sunak is desperate not to let him speak so he can say "he has no plan". It was so painful I couldn't watch it all.
I don't think it will change things though because Sunak can't avoid the fact everything happened on the Tories watch.
I did enjoy Starmer reminding everyone about the pledges though. But he'd have done better with on of our "halve growth, stop the NHS" jokes...