"I don't... I don't know" she hopes they're not dead, but she really doesn't know what dead looks like for the dead person. All she really knows is that it means people go away and lots of other people saying meaningless things they can't know like 'they're in a better place now'

"We can't be dead" maybe if she says it firmly enough it'll be true, "We can't be dead because- Because my team wouldn't let that happen, that's why."