A caregiver's ability to function may be severely hampered if trying to evacuate a group of people in -20 degree weather with bare feet. In most situations, it is better to simply call in the emergency and then check out the problem. Fire trucks can always be turned around. If there is any doubt, however, evacuate first and notify later. Plan, Plan, Plan.
Smoke detectors are very sensitive and usually give very advanced warning.
Often-times, simply putting out the fire is the best way to reduce the emergency. You may still need to evacuate due to a contaminated atmosphere. There is no action that you can take to reduce a CO emergency except to simply evacuate. Again, when in doubt, always evacuate first. Each person has his or her own bedroom.