Don't take air from a scuba diver unless you are a trained scuba diver yourself. It is well known that gasses like nitrogen dissolve in blood and body tissues. Under pressure, more gas dissolves. If you ascend too fast, the gas will form bubbles, and these bubbles can cause any sort of medical problems. Today this phenomenon is well understood.
Divers use decompression tables and computers to determinate how they can safely ascend.
You must, of course, know how to use this equipment. Use it with care and common sense. I told you that you must know this and remember that and so on. Unfortunately, under pressure the human brain does not work correctly. You might forget the most simple things.