E. coli is way cool! All my research has been on E. coli and I love it. So easy to work with! Also, I love those E. coli plush animals things, they're pretty great haha.
Anyway, I'm certain that the 30% stat was previously posted on their website, but I can't find it now. It was a little lower, more like 28%. Either way, my advisor also told me about this stat and I believe him since he participated in the admissions process at MIT until 2001. I think it has to do with the fact that there are so many faculty members in the department. I don't really know about other top schools (besides Princeton which admits around 9-10%), but I've heard they're not higher than 15-20%. This might be false, but whatever.
You will probably be fine. They called me asking me about one of my recs which was apparently missing, and then e-mailed me a day later telling me that they had found it. The lady told me that they have tons of papers and things all over the office and that some of the papers end up forgotten in the Graduate Admissions office for a while until someone sees them and sends them over to the department.