Continued knocking (επεμενεν κρουων). Imperfect active and present participle. Now all heard the knocking.

When they had opened (ανοιξαντες). First aorist active participle of ανοιγω or -νυμ. The whole group rushed out to the courtyard this time to make sure.

They were amazed (εξεστησαν). The frequent second aorist active (intransitive) indicative of εξιστημ.