You would be surprised at how much water can come through a small tear. If there is an atmospheric pressure differential a suction can be created that pulls water in to the lower pressure area. Also are the seals being uniform ally compressed around the opening when the slide is out? A slight unevenness can diminish seal effectiveness.
3 Humans,2 Dogs,1 Vision, sharing a Winnebago Sightseer 35J on a Workhorse Chassis. Allen, Donna, Drew, Bella & Pippy in the MH we call Glor-E-B!