Here the story line shifts back to Jesus. The soldiers and Jesus' accusers bring him to Caiaphas. Verse 28 gives us background information about why they did not enter the Praetorium. (See: [[rc://en/ta/man/translate/writing-background]])
Here it is implied that they are leading Jesus from Caiaphas' house. Alternate translation: "Then they led Jesus from Caiaphas' house" (See: [[rc://en/ta/man/translate/figs-explicit]])
Pilate was not a Jew, so if the Jewish leaders entered his headquarters, they would be defiled. This would have prevented them from celebrating the Passover. You can translate the double negative in a positive form. Alternate translation: "they themselves remained outside Pilate's headquarters because Pilate was a Gentile. They did not want to become defiled" (See: [[rc://en/ta/man/translate/figs-explicit]] and [[rc://en/ta/man/translate/figs-doublenegatives]])