Originally Posted by 007MI6

Honestly, the code was probably thrown as the MAF sensor was giving a false reading, due to the tube not being connected. If this sensor reads incorrect the computer will feed the wrong amount of fuel for the air that is incoming, causing a rough running engine. It is very unlikely that anything harmful happened to anything. The engine bays on these cars are sealed quite well. So unless you went "four wheeling", I highly doubt anything significant got in there. Just reconnect the tube and reset the ECU and all should be fine. Shouldn't be any damage.