dear,
if ur call registration expired less then 2 months not a problem for that , and if u have medical proof that u was going to hospital for emergency , dont worry take that one to officer there and talk to him and i am sure he will waive it , one of my freind had same problem and they waived his fine bcoz he was having medical certificate for the same time and same date , dont worry just go to traffic department in madinat khalifa near immigration office .