John Gill Commentary Acts 12:18

"Now as soon as it was day, there was no small stir among the soldiers, what was become of Peter." — Acts 12:18 (ASV)

Now as soon as it was day
When it was morning; as soon as there was any light in the prison, by which the guards could discern one another and their prisoners:

there was no small stir among the soldiers :
the two between whom Peter slept, and the rest of the quaternions that were employed in the wards to keep watch; who were now all in an uproar, and in the utmost concern and fright:

what was become of Peter ;
whether he was in any other part of the prison, by what means he could escape, and whither he was gone.