Angels in the Lucan corpus

The Church collected two books which were written by Luke in the New Testament. They are the Gospel according to Luke and the Acts of the Apostles. For convenience's sake, I will call them the Lucan corpus. The Gospel tells us the life of Jesus, and the Acts the development of the early church. The two books were dedicated to Theophilus, probably a noble, or a fictitious character created for literary purposes. Theophilus literally means "People whom God loves", or "People who love God". Both ways, Theophilus represents believers in Christ and they wanted to know more about the life of Jesus and the early church. Therefore, Luke wrote for people who had already believed in Jesus. He didn't need to persuade them to believe. Rather, Luke wanted to raise the spiritual maturity of believers. Luckily, we don't have one official gospel but four. We are able to compare stories reported by them and appreciate the different perspectives as seen through the eyes of four evangelists. In the Lucan corpus, angels play a non-trivial role. Other than acting simply as God's messengers, angels delivered the believers from dangers. What a reassuring idea.
In the story we read in Acts today, angels made their second appearance. In Acts, angels first appeared in the Ascension of Jesus. They told the apostles that Jesus would come back at the end of the world (Acts 1:10-11). They played the messengers role. In this second appearance, the apostles were arrested and put into prison. An angel played the deliverer role. The world of Lucan corpus is permeated with spiritual beings, bearing witness to the presence of God on earth.
Nowadays, people have been brought up with the milk of science and technology. Our world is permeated with fanciful gadgets without a soul, bearing witness to the triumph of scientific thoughts. Therefore, it is easy for scholars to dismiss angels and miracles. So, how do we deal with this miraculous releases of the apostles without angels. Here is how Luke reported the incident and see if we can do without angels.
But when the officers came, they did not find them in the prison, and they returned and reported,
"We found the prison securely locked and the sentries standing at the doors, but when we opened it we found no one inside." (Acts 5:22-23)
If we believe in what Luke reports, the prison was securely locked and sentries standing at the doors. But the apostles were missing. How do we explain their prison break? According to Luke, the apostles did not escape. They went to the Temple to preach at daybreak (Acts 5:21). They were very bold and were not afraid of being arrested and locked up again.
One possibility was that the Christians outside bribed the prison guard and had the apostles released. But that would incur much money because they would surely be arrested again. Furthermore, Christians were supposed to be moral people and bribery would be very out of character. Therefore, their preaching again in the Temple rules out the possibility of bribery.
Now, if the prison guard and the sentries were Christians themselves or just sympathizers, things would be easier and the Christians did not have to spend even a single cent, not now, not in the future!
Therefore, if you do not have the appetite for any angels, the second possibility is quite an attractive explanation. Still, it fails to explain why this sympathizer would tell the apostles to preach in the Temple. Surely they would be arrested again and why bothered to release them in the first place. Moreover, he must make the sentries swear loyalty and silence. Otherwise, he would be in deep trouble.
"Go and stand in the temple and speak to the people all the words of this Life." (Acts 5:20)
I do not know of any other explanations without angels. What do you suggest?
Angels or no angels, we can be angels. Nowadays, there is a resurgence of interests in angels and other spiritual things. Many edifying little stories are spreading around on the Internet on how angels appear when and where we are in deep troubles. They look like ordinary men and women. Probably, they indeed are. However, when proper situations arise, God may send you and me to extend a causal tendering generous helping hand to someone in need. We can be angels.

Dear Lord, I have been very lucky to have You sending many angels surrounding me. I pray for a more generous heart so that I can be Your angel to bring good news and deliverance to people in need. Amen.