Need help or suggestions with alsation after he has bitten?

we have a four year old alsation frasier, who has always been a saint he is great with our two children and i am his master but last night after our youngest went out to play she did not close the front door and frasier got out, and he a sod to get back in. i got him on his lead but he started pulling not wanting to come back in the house so i took him\for a walk but when we got back he still refused to go in the house, he started growling and then just snapped and bite me several times not hard but enough to break the skin, my doctor has put me on antibiotics in case of infection, BUT i have to think of my children i am seeing the vet later today i am thinking because of our children and others in the street i should have him put down what would you do. HELP. if he can do that to me his master what if this happens again. HELP