Yes, the Marines need our prayers. It is almost a given that even if the Embassy were under direct attack the Marines would not be given permission to defend either embassy personnel or themselves. Don’t believe me? Do you remember Tehran, 1979?
And?
Marines do the jobs no one else can, could, or even should do. If that means dying, so be it.
If they are going in there "heavily armed", bet your ass that there won't be a full magazine left if their position gets over-run. Regardless of RoE.