Its not what Tatum says, but what he (and the others) do. Tatum has always been "chill". JB has always been much more vocal and willing to call teammates out to play harder. White, Holiday, and Porzingis are the missing pieces, both from a talent and mindset perspective. Losing Porzingis was a big blow.
I still like the C's to in the series, but if the C's lose tonight and it goes the distance, the amount of pressure in Game 7 will be supernova - and probably will affect players' performance. Yankees were shell-shocked in 2004 Game 7, and didnt have a chance.