I have not been to those tubes, but from what I read: entry at 90ft and exit at 40ft. Without knowing how wide they are, if there is flow in there, what sediments are on the floor, walls, can you see daylight etc, etc...... I would be cautious.
My view is that while emergencies never go planned, if you plan for emergencies, at least you have the mindset and cool headedness to handle them. You dont want to be in a situation where you handle an emergency for the first time on your first dive in an unfamiliar environment. More over, when you are with a buddy you have not dove with before.... how do you know you can help each other, that no-one is going to panic and actually knows what to do. I read in this thread, depth, lost mask, OOA etc. These are all very valid points. And I would like to add: in the tube you may not have direct access to the surface, you may silt it up, you may be in a total black out (again I have not been there). Do you have the right lights, equipment to handle emergencies, what would gas planning look like (to also allow for emergencies).
I would advise against going into overherad environments without proper training. But if you do want to do it, at least think first about how you are going to handle situations. And above all, if it doesnt feel right..............call the dive. Many cave divers call dives simply because ' it doesn't feel right'. And that is okay, no discussion, no argument from buddies.
All I am saying is think it through......