How do you put up with fire tower training with full gear?

Even with captain giving me hard encouragement I just die halfway through the exercise I just feel like who needs oxygen so I throw the tank off my back even if it's empty for training seems like I'm unfit.

My captain told me he did this with a dummy on his shoulder 30 times fully equipped now that's mega impressive atleast for me.

(Won't lie I struggled hard carrying that dummy in the underground rescue exercises) it was mega cramped hard to breathe with no vision and very wet.

Cap said I would of killed the person I was rescuing in those practises from a broken neck yeah don't drag em around sharp corners like I did by their legs throwing the dummy hard out of the tunnel that probably caused that (I was majorly fed up at that point no matter how many times cap said he could get me out from underground if I needed it)

Have you ever had underground training? How did you put up with it? I just dragged the dummy behind me and failed.