17Peter motioned with his hand for them to be quiet and described how the Lord had brought him out of prison. "Tell James and the brothers about this," he said, and then he left for another place.
18In the morning, there was no small commotion among the soldiers as to what had become of Peter.
19After Herod had a thorough search made for him and did not find him, he cross-examined the guards and ordered that they be executed.
They, meaning more than just Rhoda, went back to answer the door. Partly because they knew Heord had already taken Peter as prisoner, who would be next?!? They were AMAZED when they saw Peter before their eyes! There must have been a loud sound with all the rejoicing, for Peter motioned to them with his hand to be silent.
Quickly & quietly Peter described his unbelievable miracle, then left to go into hiding. Luke did not record his whereabouts, this episode is the last major incident in the life of Peter recorded by Luke.
The James that Peter was speaking of was the brother of Jesus.
Harsh but true, under Roman law, guards who allowed a prisoner to escape were subject to the same punishment the prisoner was to receive. Thus these 16 guards were sentenced to death.