Contact the coach ASAP. Coaches at MIT have very little clout with admissions, but they do send a list of athletes they would like to have on their teams. I don’t think MIT even gives likely letters. But that does not matter in your case because you are late to reach out to any coaches. But you are a SPRINTER and as such your times speak for themselves. Since you say your times stack up well, then he can evaluate you pretty quickly. MIT track does publish a list of qualifying times for all events that includes times they expect of recruits and times that will qualify you as a “walk on.” See if you can find that list with a google search. If not, the coach can share it with you. A simple email to the coach with your times and letting you know you applied could not hurt. Attach an athletic resume to the email if you have one. Hopefully you get admitted with or without coach help and having contact with the coach will make joining the team more smooth. Don’t show up first day of class expecting to walk onto the track team. No doubt there will be summer training expected. Good luck!