Avery watched anxiously as the distressed animal inched its way forward, its eyes fixated on the shining blade. Although Avery was reluctant to move any nearer, he remained firmly rooted to the ground, with no intention of taking a step back.

Yes, "Time extended, each second seeming like hours" is a correct sentence grammatically. It is commonly used as a metaphorical way to describe how time seems to pass slowly due to a feeling of boredom or impatience.