Release it now. I'm a psych resident and don't know a lot about IM specifically, but my guess is that any place that cares enough about step 2 that you would be at risk of being screened out based on a score in the 240s might also not offer an interview to people who don't have a score available.
If I was a program director, I would not be a huge fan of any unknown variable that could get in the way of licensing.