Completely impractical is correct. From an ABC 4 Corners interview with one of the expert cave divers involved:
TRANSCRIPT EXCERPT:
> JASON MALLINSON, BRITISH CAVE DIVER: "They had a full-face mask on.
So, it was basically that one thing that if the mask that they were using became dislodged and water entered that mask and it- couldn't get it out, that was the one thing that would kill them.
You got to a section, you know, th-the vertical section we was talking about, and by that time you've been in the system for five hours.
You don't remember where the vertical section is and the only time you find about it is when your head bangs against the wall there.
And you, you're trying to get yourself through this vertical section, but you can't remember exactly how it's laid out
So, I'm trying to get myself through it, but I'm also trying to get a kid through it, who's vert- sort of horizontally in the water.
Trying to post him through - no, that doesn't work; pull him back.
Trying to post myself through - that doesn't work.
And you could spend several minutes at one, just one obstacle to try and find your way through.
And you know, eventually we did it, but it's a very slow process and quiet, quite daunting."
TRANSCRIPT EXCERPT:
> JASON MALLINSON, BRITISH CAVE DIVER: "They had a full-face mask on.
So, it was basically that one thing that if the mask that they were using became dislodged and water entered that mask and it- couldn't get it out, that was the one thing that would kill them.
You got to a section, you know, th-the vertical section we was talking about, and by that time you've been in the system for five hours.
You don't remember where the vertical section is and the only time you find about it is when your head bangs against the wall there.
And you, you're trying to get yourself through this vertical section, but you can't remember exactly how it's laid out
So, I'm trying to get myself through it, but I'm also trying to get a kid through it, who's vert- sort of horizontally in the water.
Trying to post him through - no, that doesn't work; pull him back.
Trying to post myself through - that doesn't work.
And you could spend several minutes at one, just one obstacle to try and find your way through.
And you know, eventually we did it, but it's a very slow process and quiet, quite daunting."
http://www.abc.net.au/4corners/out-of-the-dark/10000580