Three more minutes had passed by now.
Henry was annoyed, but deep down, he was also getting anxious. Over half thirteen minutes had gone by—where was the ambulance no one knew. He couldn't even hear the siren of an ambulance.
He'd just called City First Hospital, and they told him the ambulance had left very minutes ago, right after his first 911 emergency call. They said it was dispatched immediately.
But now, more than thirteen minutes have passed since that call.
How could Henry possibly know that until the main character finished showing off, the ambulance wouldn't show up?
For the full explanation, just look at some movies: the bad guy dies, the hero limps out covered in wounds, and only 'then' do the police cars roll up to the scene.
Alex coughed lightly and kindly reminded, "Aren't you going to save someone? If you don't hurry, the ambulance will get here first."
Honestly, it takes way too long for the doctor type of hero to show off.