This was always the issue when it came to fighting the Doctor. Alice knew it full well ever since their first exchange in the north, and it was only proven further right now.
No matter their firepower, there was something different about the Doctor. Something that kept him alive no matter what.
She couldn't even use her artifact either since she was technically hitting him.
Just not the 'thing' keeping him alive.
His soul and physical body were here. Or at least from what Alice could tell. But there must be a 'core' that kept everything intact.
And without destroying that core, killing him was impossible.
'Cayla, did you see anything that might help us find out why this prick is immortal?' Alice asked, but Cayla quickly shook her head.
She had already been cross referencing everything she'd seen thus far, and nothing she'd found could help in their case.
This was a completely original creation by the Doctor with no prior information at all.
