So Mr.Assange has declined to surrend him self at this time. This should not be seen as a insult to the local police and the order, at this point the international law would take precedence. Once Ecuador has reviewed this application he will either leave or stay. If he stays he might never leave the embassy, and there is no way for the embassy to get him legally out of the country. Once he leaves the grounds he can be arrested. The other alternative is that he lives in the embassy for a really long time, years to decades.
Technically they could try and close the embassy then he could be taken in to custody.