A lot of fun banter between the Marines and a clearly apprehensive Archer. I especially enjoyed the vaguely homoerotic tensions between James and Partridge.
Overall there was a little bit too much exposition here for my tastes. At some point this turned into more of a show-and-tell and if I were Archer I would have had some choice words for the Marines for that little light-show stunt without a proper warning.
At least now that we're all familiar with their gear, we get a sense that the Marines should be ready for whatever they're going to encounter in those tunnels. But ... will it be enough?