I considered your coachman to be a faithful man, and I told him to wait for you at the postern.
He knocked, and presently the postern gaped, and a lantern was advanced.
As each man did so he had to retire by a postern leading to the sea.
Cowper assumes a second postern, but there is no evidence for this, and l. 139 ff.
If I do but send them a message they will surely come ...