Because if Tom was in a wheel chair, obese, or had a bad back he probably wouldn’t have been able to defend himself:
We train to be functional. You never know if and when emergency situations could happen. You may have to pull yourself out of a burning car, lift a heavy object off of someone, or defend yourself from the drunk guy on the bus. The better your general physical preparedness is, the better off you will be when something happens that you might need to “fight or flight” (hopefully that earthquake holds off for a little bit longer).
Your virtual objective is to save a child at a top of a mountain. Once you reach your target the mission is done, but it’s a long way to the top. Manage your pace and rest to get it done as quickly as possible:
Run up 9 flights of stairs (elevator down is your rest)