A flashlight is a tactical too like your firearm and should be held in your offhand if you need one.
If your light is on your gun in a self defense situation you need to point your gun at loved ones to assess health or injury status. If its attached you need to manipulate the firearm to remove it to use it without pointing the gun. If its mounted to the gun it cant easily be used as a thrown object.
I prefer to set the light down shining down theexpected qpproach point without holding it letting the goblin know where i actually am. This way he can shoot at the light source and i can defend from safety while waiting for the police.
No it isn't that bad its does make it seem like things are moving a little slower than they actually are. Depending on the environment your in a light mounted on your gun might be better. For example if you had to open 2 doors a light on the gun leaves a free hand to open them and you would still have light pointed towards the source instead of at the floor from turning the handle.
Until the threat is gone one way our the other, you shouldn't be worrying about triage. If they just hurt your family they have no problem hurting you. if you take your attention off of the threat you will more than likely get hurt to.