Anaphylactic Shock is nothing to take lightly. It is deadly.
I had had an anaphylactic reaction to an IVP, and it was the scariest thing one could imagine; throat closed up, eyes swelled shut, couldn't breathe, etc., was literally suffocating. And couldn't get the attention of the doctor and tech, who had their backs turned. It is most certainly serious, and I nearly lost my life with medical help two feet away.
Some poor kid out on a date who doesn't get the shot immediately is in big, big trouble. I truly don't know if I could have given myself a shot before it was too late.