You can take the rapid course which is to be jabbed on day 1, day 7 and day 28. You will be protected for a short time (provided that you are receptive to the type of innoculation) but the effect will not last as long as the protracted course. Also, if you have been vaccinated for Hep B before, you should have a Hep B titres first, you may well still have sufficient antibodies, some people can make one course of hep B last a lifetime!
The absence of innoculations does not exclude an individual from deployment (otherwise, we'd never manage all of those last minute "pings" from on-high). However, the process of innoculation must be begun before deployment and the risk posed to the individual raised in their medical documents (for innoculation to continue in theatre) and to the CoC so that the individual is not inappropriately employed before innoculations are complete.