You're reading too far into the Orbital thing, while misunderstanding the 'Shock' in ODST, while misunderstanding what an ODST even is, all at the same time.
Though I will admit that the chest plate is similar.
English
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1: Shock means when they land harshly, they're shock absorbent (Taking not as much fall damage) they're using similes. 2:ODST spec ops. marines sent in before the spartans to clear it out if marines can't. If they can't they bring spartans.