A combat medic was "not told to read" Ministry of Defence guidelines on preventing deaths from climatic injury before a fatal SAS test march, an inquest has heard.
The soldier, known by the codename 1H, said he had "not really looked at" joint service guidance advising that military exercises should be called off if a heat injury is diagnosed.
Giving evidence at the inquest into the deaths of three reservists amid "boiling" temperatures in July 2013, 1H also conceded that an air ambulance should have been put on stand-by during the march.
Lance Corporal Craig Roberts, Lance Corporal Edward Maher and Corporal James Dunsby died after collapsing due to the effects of heat in the latter stages of the 16-mile (26km) "selection" test in the Brecon Beacons in South Wales.
On the fifth day of the inquest in Solihull, West Midlands, soldier 1H was asked if the air ambulance and the Welsh Ambulance Service should have been put on notice due to the weather conditions.
The medic, a member of 34 Field Hospital who was serving alongside a Signals regiment, said: "In hindsight, they maybe should have been put on stand-by, but I didn't think to then."
Questions were also put to 1H about a joint services document containing a treatment algorithm stating that military activities should be halted if a heat injury is reported.
Coroner Louise Hunt asked 1H: "Did any of your training confirm that if you had a heat-related case, the algorithm suggests that the military activity should be stopped and all personnel involved in the activity should stop if the operational environment allows?"
Giving his answer from behind a screen, 1H responded: "I wasn't aware that all activity had to be stopped.
"In our medical training we do go over some documents but, as you can understand, there are quite a lot of documents."
Referring specifically to the joint service document on climatic injury, 1H added: "They are just there as guidelines. I have not really looked at it myself."
Soldier 1H said he had looked at the document since 2013 but added: "We were told it's just guidelines and we are not told to read it.
"We are basically just told we don't have to read it."
The medic, an Afghanistan veteran, took part in efforts to revive L/Cpl Roberts after his collapse at around 3.30pm, near the final march checkpoint.
At 12.46pm on July 13, the combat technician was also involved in assessing soldier 2P after he was medically withdrawn from the march with a heat illness.
Asked how severe 2P's condition had been, 1H told the coroner: "I have seen worse in Kenya and places like that. On a scale of one to 10, he was a six maybe.
"I think, throughout, I did pull some people off the march that felt they didn't have to come off, so I think I was pretty vigilant."
Emergency medical technician Wayne Thomas also gave evidence to the inquest, describing how he joined attempts to save L/Cpl Roberts on the hillside near Beacons Reservoir.
After making his way across fields alongside a mountain rescue team, Mr Thomas emerged from trees, looked up and witnessed Army personnel performing CPR.
Mr Thomas then took over from an Army medic, carried on with CPR and used a defibrillator but found no "shockable" heart rhythm.
Paramedic Geraint Tucker also attended to L/Cpl Roberts, giving him adrenaline.
"We made every effort," Mr Thomas said. "From what I saw, everybody I came into contact with that day tried their hardest and their best."
The inquest heard that an official document drawn up ahead of the march wrongly listed the nearest hospital as being in Abergavenny, rather than Merthyr Tydfil.
L/Cpl Roberts, originally from Penrhyn Bay, Conwy, was living in Lee, south-east London, and worked as a teaching assistant in the capital.
He was pronounced dead on the mountainside after comrades and medical staff spent more than two hours attempting to save him.
L/Cpl Maher, who was born in Winchester, died later the same day in Merthyr Tydfil's Prince Charles Hospital.
Cpl Dunsby, who lived in Trowbridge, Wiltshire, died on July 30 after being transferred to the Queen Elizabeth Hospital in Birmingham.
The inquest was adjourned until 9.30am on Monday.