The court heard that Ewan started to feel faint shortly after he and his father started the walk around 10 am.
The pair found a cave and Ewan's dad gave him some water. They then returned to the track, but became disoriented.
About 400 metres from the car, Ewan complained he could not walk any further. His father then sat him down and continued to the car to call 000 at 2.03pm.
The call lasted seven minutes and was logged as a a "priority three" job by WA police.
The job's status was upgraded to "priority two" four minutes later when a call was made to Exmouth Police Station alerting them about Ewan.
State Coroner Ros Fogliani will look into the handling of the call by officer Sen. Const. Diviney.
Mr Williamson said he initially "wasn't concerned" for his son's life, the ABC reported, but when he returned he found his son was semi-conscious and called again for an ambulance.
Two Exmouth police officers arrived just before 3pm and then carried the teenager up a gully.
Paramedics attempted to resuscitate the teenager but he died in hospital that evening.