Running during a swim?

I did my first OLY yesterday... but I question the swim and I figure someone out there knows if this is really a USAT rule?!  We had a long narrow swim in a lake, but it was about as wide as a river.  One side was along a sandy beach, the other was in the middle of the lake.  We had to do 2 loops, getting out in the middle and running across the timing mat.  It started off fine, 2 waves went off, but on the 3rd wave, the air horn went off and one woman ran on the beach, but yes she was running in the water and then she started swimming right at the first turnaround buoy... of course, we were all stunned, but the announcer said that yes, this was legal according to USAT rules.  My wave went off with only about 3 of us actually swimming at the start, the rest did the run thing, and when I came around the second turnaround buoy, I swam about 1/3 of the way towards where we had to get out to make our second loop and saw that virtually EVERYONE was running on the edge of the water and were obviously going faster than I was swimming, so I got over to the shore and ran too.  This seems like an obvious advantage to the runners and I felt like it took away my advantage as a swimmer!  Basically on the 1 mile swim overall, a full half of it was running along the edge of the water as opposed to swimming. 

Thoughts??