Some of the exercises for the more 'sneaky-peaky' regiments *have* to be exacting. The participants are given a task and a time and have to complete it without supervision; or at least there are large portions of time where supervision is not possible.
It is a tragedy that these deaths occurred and the wisdom of letting this sort of exercise [as there are few details it isn't possible to comment further] take place in the sort of weather we are presently experiencing, ought to be questioned.