Another look at the ventilation shaft. There are no guard rails or retaining walls and the edges slope inwards lined with slippery sand. You are advised NOT to go into this tunnel or near the ventilation shaft - it is too dangerous and the nearest competent help is many tens of kilometers away. You are also advised not to chuck stones in the shaft - it would scare the bats roosting in the tunnel.
Please do remember the cardinal rule for the IRFCA (as for any responsible) trek: Do not to disturb any wildlife or plants and do not to leave any evidence of your visit (no garbage left behind, no "XXXX was here" sort of marking).