Forum:The Opposing Force plot makes absolutely no sense to me...

If the Black Ops were going to nuke Black Mesa, which would surely have destroyed the Gene Worm in the process, then why would the GMan have any use for Shephard? It was the GMan's plan to nuke Black Mesa from the start, so Shephard wound up serving no productive purpose at all.

Could someone explain why the GMan would go through the trouble of dealing with this grunt?