"P-P-Potter," stammered Professor Quirrel. He grasped Harry's hand.
V.S.
"P-P-Potter," stammered Professor Quirrel, grasping Harry's hand.
In the first sentence, it feels as though Professor Quirrel waits for a second or two after talking to grasp Harry's hand while in the second sentence, it feels as though Professor Quirrel immediately grasped Harry's hand after talking, right?