A Small Puzzle About Aragorn

Fired up by all this news of a movie(finally), it seemed like a good time to start my yearly re-read of LotR and now that I have found a forum of like-minded folks with whom I can question some of the things that don't make sense I wanted to get some feedback on a small mystery.
During the Fellowship's trip through Moria, when they come under attack in the Chamber of Mazarbul, Aragorn's first advice is: "Slam the doors and wedge them!" in anticipation of gaining the opportunity of cutting their way out. When I was younger, this went right past me, but maturity has made me question this. Now Aragorn at this point is eighty-something(if memory serves me correctly) and has served in soldierly positions for a number of years in a number of places and presumably has gained much experience on the right way and the wrong way of doing things. Now my point is: why would Aragorn have made such a dumb call? The Fellowship already knew that they were likely outnumbered, probably quite badly. Of the whole group, only two or three are really warriors. Aragorn should have known that you always leave yourself a way out. It is a horrible mistake to plan on trying to escape after you are cut off, especially by large numbers of enemies. I don't care how strong your position is, if you only have small numbers it is unlikely that you will be able to hold that position long enough to derive any real benefit from it.