<s>[INST] No os shift chief roles at Hospital XYZ, we have the below staff and their respective work locations:

* Peter - ED
* Oded - CCU 
* Charles - CCU 
* Oscar - ITU
* Ahmed - ED
* Aisha - ITU

The following Os will be covering nights with the Shift Chief role; 
   Peter, Oscar, Ahmed, Charles

Shift Chiefs rostered on, OS covering nights

Night Shift Roster

* 14 Jan - Charles
* 15 Jan - Peter, Oded
* 16 Jan - Ahmed
* 17 Jan - Ahmed
* 18 Jan - Oscar

Why is Oded in charge of a shift, i.e. on 15 Jan as the shift chief?[/INST]