Also, don't suction more then 10 seconds or the patient will suffocate because you've sucked all of their oxygen out. (That one is from class.)
The Intermediate/Paramedic equivalent is this:
You must preoxygenate your patient for two minutes before you intubate. You then have EXACTLY THIRTY SECONDS to successfully tube the patient. If you don't do it in thirty seconds, reoxygenate for another two minutes OR YOUR PATIENT WILL SUFFOCATE AND DIE A HORRIBLE DEATH AT YOUR HANDS.