After which word should you place a comma?

He screamed called for help pounded on the walls with his fists.

After which word should you place a comma?

He felt a worrying shudder in his chest as if his heart wanted to escape to flee his body.

After which word should you place a comma?

A straight line of light appeared across the ceiling of the room and Thomas watched as it expanded.

After which word should you place a comma?

Thomas looked back at his captors feeling awkward but desperate to ask questions.

Which comma rule is present here?

One boy's eyes, flared with hatred, stopped him cold.

Which comma rule is present here?

Shaken, Thomas stared at the boy's back until he turned and took a seat.

Which comma rule is present here?

He paused, and Thomas realized his face must've whitened even more when heard that last part.

Which comma rule is present here?

Alby spread his arms out, palms up.

Which comma rule is present here?

Thomas folded his arms, closed his eyes, took a deep breath.

Which TWO comma rules are present here?

Thomas said nothing, his eyes staring at the cracked, rocky ground.

Which TWO comma rules are present here?

He'd reached the door, an ugly slab of sun-faded wood, and he pulled it open to see several stoic-faced boys standing at the foot of a crooked staircase.

Which TWO comma rules are present here?

No one made a move to stop him from doing as Gally asked, except for Chuck, who stood at the front door, shaking his head.

Which TWO comma rules are present here?

At least twenty feet across, the break in the wall went all the way to the top, far above.

Which of these is a RULE about COMMAS?