That happened to me a lot too, when I played with this deck...
Here were my thoughts at the time:
It seemd most of the time it was against FGs with a few big creatures (decks you don't always win against in the first place)
or
It was against higher win FGs, that had a heavier rush, but one of the two draws didn't happen
a 2nd firestorm to kill off some of it's higher HP creatures along with the cells.
or
a dim shield didn't show and I was going to die prematurely.
So I was often in the forced count damage routing, of how much am I going to get, can I survive the next attack, does this FG heal and if not, can I do a 100 damage hit now, block the damage with the chimera, resetup in time, etc, and then either choose to quit because it's a loss or keep playing because I could win...
It's actually why I recommend LS over this for newbies, even though I won more with this, I wasted a lot of time wondering will the combo come and work in time... I'm certain if I played it more, I could make the call pretty quickly on the first couple rounds how the game will go, but I was well past the point where I would regularly use this deck by the time I saw this, and didn't invest the time.