The place where Peter denied Christ –
The entry doors depict Chist warning Peter about the denials.
The image being the altar is Christ (above) and below the last supper.
Huge icons
Peter denies Christ
Peter realises his denials as the cock crows
Peter reconciled with Christ after the resurrection when fishing on the Sea of Galilee & Christ eats with them.
As the denials occurred at Caiaphas’s house, the discovery of an altered ritual bath (turned into a prison) may have been where Chist was kept whilst the Jewish leaders decided what to do with him.
The church floor has the opening for dropping a prisoner into the prison. 
Father M 