Yeo acknowledged how difficult it will be for the Blues to find that line Friday.
"It's a very fine line," he said. "That's our challenge right now. So for me, I want to see us play this game with confidence, I want to see us go out there and execute and be aggressive in our game. But you have to make sure you don't go over the line and beat ourselves in a lot of the ways that we did last game. The flip side of that, you can't be uptight. There's no reason we shouldn't be confident tonight. We know it's a tough task, we know that it's a good hockey team and we know how big the game is. Every game is big in the playoffs."
But not every game in the playoffs has the consequences of this one, and it's a situation the Blues haven't faced yet after going up 3-0 in their first-round series against the Minnesota Wild and winning it in five games.
The line Yeo was referring to concerns urgency, and how if you don't have enough you can get buried by the opposition. But if you have too much you can bury yourself.
"Sometimes you start overplaying things and you start to overlook things and start to get maybe too aggressive in certain areas and you can generate offense for them or generate opportunities for them," Parayko said. "It's the ability to make the reads on the play, and if you're going to be aggressive in certain areas you know that you have teammates in their spots to back you up."
The urgency line is one the Blues absolutely must straddle if they hope to tie the series and avoid being in a 2-0 hole heading to what surely will be a raucous Bridgestone Arena for Game 3 on Sunday.
In order to do so, they probably have to avoid thinking about what happens if they don't.