Inspect the wall, there you'll find a small ledge which makes it possible to shimmy to the other balcony.
I don't understand to which side you refer to when you say "left". On one side you have a very limited range, the way is immediately blocked by barrels. It should be easy to jump to this side and then shimmy to the other one as said above, this is what I did.
On the other side you walk all the way until you reach a pile of barrels. There is a gap between the barrels where you can see a med kit waiting for you. If I remember correctly I managed to crawl through this gap, it was a bit tricky but finally worked.
I remember this location quite well and think it might be also possible to hang down the ledge and shimmy past the barrels, I however didn't try.
Once you have passed these barrels the rest should be easy. Hint: when you reach the door and go upstairs you should carefully look around, especially on the ceiling, there's something valuable...