Sorry, but the only way to become fully competent with MedSurg skills is to work in that environment. There's just no other setting that will not only provide you with the opportunity to gain technical expertise, clinical reasoning and organizational skills needed to function effectively in 'crisis' situations. Of course, if you are interested in the administrative/planning side, that is a completely different skill set but would also require a basic understanding of how patient care occurs.
FYI - my organization (large faith-based health care system) has fielded teams to assist in disasters (e.g., post hurricanes, Haiti earthquake, etc). Those teams consist of clinicians with specialty expertise/skills in ED, OB, OR & Pedi - nurses & physicians. Prior to their deployment, they are also given additional training needed to provide basic ancillary services (lab, EKG, Resp Tx, Radiology). And, of course they have to be willing to "camp" for weeks at a time since housing is rarely available. They go because they have a passion for this type of initiative - they only receive their regular salaries as well as travel/lodging.