2003 Chevrolet Impala 2 Questions

Hi, my first question is that when anytime that it rains and my car sits outside, the passenger side floorboard becomes very wet and I was wondering how is that possible? The second problem that has occurred just happened on Monday. I was driving home from work when this constant clicking noise started to happen and it has something to do with the lock/unlock button because that is what it sounds when I lock or unlock the car. Now in the morning, it will be noiseless, but when I am driving home from work, the lock/unlock button noise is very constant when I am driving. When I am stopped, the clicking noise will stop though. What could this noise be from since I dont hear it in the morning, but hear it in the afternoon? Thanks and looking forward to hearing from you!