Sub-Internship (IM)

How essential is a sub-internship prior to applying? Long story short - our school's lottery did not work out as I hoped and I will not be able to complete a home sub-I prior to October. Should I try and get away with just doing a subspecialty elective at my home institution (eg, ICU)? Or should I try and land an away sub-internship (which to me sounds too risky)?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Internal Medicine and IM Subspecialties Source Type: forums