Not sure if this has been posted but here is a neat little trick
after you load in to the instance head to the shift leaders talk to them and tell them to deploy the troops once they do talk to them again you will get a option to tell them to move out w/e:P choose it then talk to them again and you can deploy more troops keep doing this as long as you want or untill the commander spawns with your very own army of miners you wont have to worry about any npcs youll just have to worry about keeping the commander away from the miners b/c yes they will kill him

hope this helps:)
AH kk thanks then I wasnt sure of that just didnt know about it for a while and not sure how many others do so just though it be a neat thing to know 