I know that the OP didn't specifically state this, but he didn't exclude it either. Facing this scenario, if I come home to find people fleeing the house my response will be dictated by a single fact; whether or not my wife and kids are there.
Unfortunately, my wife and kids are not always with me. Sometimes they are home when I arrive. If they are home, or I expect for them to be home, you can bet that my response will be much different than "observe and report." It is unlikely that perps made it past my wife (she's been to many of my classes) but I cannot count on that fact alone.
This would be one of those few scenarios in which I advocate entering a building or dwelling without assistance or awaiting the arrival of police. I simply could not afford to. I would accept the risk, weapon drawn, and find my family. Anybody that came between me and them during my search would be fair game.
It is for this very reason, and instances like it, that I do advocate one know how to not only conduct a search alone, but undergo training that does not ignore the possibility of having to advance on or through a threat. CQB skills, even solo CQB skills, are very important. I am not an advocate of conducting a search alone or rushing through a dwelling/day care center/etc by myself, especially against potentially armed assailants. But when family is involved, dynamics change and the amount of personal risk that we are willing to accept should change as well.
If I know the home to be unoccupied, at least by my loved ones, I'll observe and report. Even working patrol as a police officer, I would always wait it out for another officer to arrive before searching a building or dwelling. It's just the prudent thing to do. But once again, when lives are at stake, especially loved ones, dynamics can change and you may be forced to rely on your own overwhelming violence of action to overcome the threat that lies within.