IM chair letter as one of three letters of recommendation for residency?

Unfortunately, It is looking very likely that I'm being ghosted by one of my letter writers. Right now I have 2 radiology and 1 IM chair letter that my school required anyone doing IM or prelim/TY's obtain. If my third individual letter writer does not write one for me in time, is it reasonable to submit 2 radiology and the IM chair letter to radiology programs or is that a death sentence because they don't count it as fulfilling the requirement?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Radiology Source Type: forums