Question

Ill or injured persons may benefit from emergency oxygen in situations that include serious bleeding, divers with a decompression injury, difficulty breathing, suspected internal injury, and:

Answer 1

it would also be warning sighs of serious illness

Answer 2

Ill or injured persons may benefit from emergency oxygen in situations that include serious bleeding, divers with a decompression injury, difficulty breathing, suspected internal injury, and: POSSIBLE HEART ATTACH AND CHEST COMPRESSION. 

Oxygen allows for the blood to become diluted and the blood vessels to enlarge that's why in emergency situations it is always the 1st part of their actions.