Complex sentence: McKeon led the platoon toward a swampy tidal creek on Parris Island, South Carolina, near the eponymous Marine Corps recruit depot, and, upon arrival 45 minutes later, McKeon jumped into the creek and ordered the platoon to follow.
Split into simpler sentences: McKeon led the platoon toward a swampy tidal creek on Parris Island, near the eponymous Marine Corps recruit depot. Upon arrival, 45 minutes later, McKeon jumped into the creek and ordered the platoon to follow.