Or get water in the engine which will cause an instant death! These engines don't tolerate water being introduced in very large amounts into the intake and cylinders and have the potential to easily bend a rod, bust a piston or window a block.
Look around, you'll find posts about the seal on the air filter breather and the cowl seal and the problems resulting if they fail just in the rain! Water doesn't compress and these engines have high compression to begin with.
I wouldn't worry about the exhaust NEAR as much as the intake. I can also tell you, these trucks are heavy, those mud holes and water pits most say have no bottom, well they do, and in one of these, you're pretty much bound to find it! Mine seen it's fair share of off road, believe me, it's get to the bottom of a situation pretty quick!