Ah Ha!
Now that I've seen the real thing, yes, that's exactly what would be done. The canopy was superfluous, so would be ditched, which would also allow quicker extraction of the drum. Also, looking at the relatively small space, it's possible that a smaller, 25 gallon (approx 110 L) drum was used, maybe even four or five 25 Litre 'Jerry Cans', and dropped in vertically. This would, I think, be better for weight and balance, being upright and about the weight of a well-built man and, given that it was secured, would probably be more stable than a drum lying on its side - there'd be enough problems flying the thing to a successful landing without adding weight shift to the mix!
It looks like it would be quite difficult, if even possible, to fit in a standard, full size, 50 gallon drum.