### Clue: Police officer gets one chance to be the captain(sic) assistant (2-5)
### Answer: CO-PILOT 
 ### Explanation: Definition: captain,(sic) assistant
 COP(slang for a police officer) **plus**(gets) I(Roman numeral for "one") + LOT(the use of lots to make a choice by chance, as in "the order of appearance shall be by lot;chance").