Dig a hole, place ladders going all the way down your shaft.

If you're looking at your ladder now, so it's dead center, place a trapdoor at the top of the ladder so that the hinge is anchored to a block on the right and covers the last ladder.

Open the trapdoor and climb down the ladder - hold shift to stop your descent.

In numerous attempts, I cannot interact with the trapdoor to close it while holding shift on the ladder. Once shift is released, then I can close the trapdoor normally.

Attached is a screenshot of how my ladder is built.