Question about the ending (SPOILERS)

I really enjoyed this film but had a problem with the ending. (forgive me if I missed something or if this is a supid quesion)

After they put on the survival suits, before they enter the torpedo shute, Robinson explains to the boy that once he fires him out of the shute, once he is in the water he needs to pull on a cord to inflate the suit and this will then bring him up to the surface. I can see how this makes sense as if the suit is inflated before entering the torpedo shute it might be too big and get stuck. So...if this is the case, how can a suit with just gold and a photo make it to the surface as there is nobody in the suit to pull the cord to make the suit inflate once it has been fired out of the torpedo shute and in the water?