You should pick up a ruggedized laptop case that is waterproof, this is the basic that it can do. There are more levels of water interaction that it may take, from rain and spilling water on it up to emerging under water.
Solid and hard to break
Built of hard materials, rugged laptop cases are tested to withstand impact. Some are very rigid and can handle crushing forces (at least from a person jumping on it) as well as high impact forces.
The interior must be coated, wall to wall, with panels of soft materials, to also protect the laptop that you carry inside it.
Adjustable interior for a lot of rugged laptops models
A good rugged laptop case must keep the computer inside it in a fixed position, to not “jump” up and down, protecting it from extra hits.
A rugged laptop case must also protect the laptop inside it from interaction with chemical elements that would normally destroy it.
OK, this may not be the detail that will convince you to buy a rugged laptop case, but surely it is a “must consider” one: Strap of a rugged laptop case. It is easy to see why you need to consider this: you will probably carry it a long way around so it would be a wise thing to protect your shoulders. At the same time pick a solid strap that will not break or damage in time.
Also you should test if it stand on it’s edge, like a regular business case, otherwise you will always need to put it on something instead of just letting it down.