The EC version came first by at least half a year. It is the first EC story drawn by Reed Crandall, and might have been a shock (heh-heh) to EC’s readers when they picked up Shock Suspenstories #9 (1953). Long time comics veteran Crandall fit right into EC’s style.
The artwork for “Trapped” is by Doug Wildey, who also had a dramatic and very polished illustrative style. (He later went on to help create Jonny Quest in the '60s for Hanna-Barbera). It appears the writer wanted to one-up the EC story with some graphic violence. In “Trapped” there is a shooting of a child, which even for a story where vultures feed on corpses, seems like an extra assault on the readers.
Speaking of assaults, this is my last posting of 2015. See you when the calendar rolls over to January. Happy New Year, all.