HALO stands for High Altitude, Low Opening. This type of parachuting technique can be dangerous. The plane would fly minimally at 25,000 feet and sometimes up to 40,000 feet where it was undetectable even by radar. At such high altitudes of the Earth’s atmosphere, the oxygen required for human respiration is scarce. Lack of oxygen can lead to Hypoxia.
When it was time to jump, your first instruction was not to open your parachute. You would literally move into a free-fall. In a matter of seconds your terminal velocity would be 120 miles an hour, though you might hit speeds of up to 200 miles per hour. You open the chute at the last possible minute, with only enough time to save your life.
With canopy deployment at roughly 2000 feet, there’s just enough time to break your fall so that you land safely behind enemy territory. If you live, you get to fight the enemy.
I think that is an incredibly dramatic and accurate metaphor for followers of Christ, who are discovering the passages of life. The journey into the promised land begins at high altitude...