I think that many shorts on AMBS are probably amateurs who have learned that shorting a penny stock can lead to huge gains is a very short time. AMBS is not however your typical penny stock as evidenced by the Board of directors, and advisors. Many of these are icons in their own right who have been struck by the incredible potential of AMBS on numerous fronts. Shorts who have not done careful DD on AMBS are in an extremely precarious position. They could wake up some morning to a "nightmare scenario" that would double or even triple AMBS overnight! The handwriting is on the wall! You may be riding a Tsunami!
Shorting a .07 stock in its self doesn't seem bright the downside at best is a few cents AMBS seems to have good support in the .05-.06 range with the 52 week low at .03 the risk reward case for shorting doesn't seem very good to me and I agree as you stated the possible up side easy 2x - 5x with reasonable news