This scene is taken directly from Law Chantler's diary, which reads:
Thursday April 29
Did my first cliff-climbing to-day. Spike Kearns & Stauffer and I, wheeled to the Sandgate Quarry and spent about an hour going up and down about 100 ft. Some straight and some slanting. Not difficult. Just requires steady nerves.
Try as I might, I was unable to find photo reference of Sandgate Quarry, so I've depicted a fairly generic-looking quarry here. I did find pictures of Kearns and Stauffer, though, so their depictions (though tiny) are correct. Also, while I'm not an expert on rock-climbing techniques or precisely sure what the Army would have taught in 1943, the climb as depicted here is consistent with '40s-era cliff-climbing photographs.