Stuff happened with Rick shooting like a stormtrooper having an automatic weapon and a wheel gun at a guy armed with a baseball bat dipped in biter guts and couldn't hit his arse with both hands. He burned through 60 rounds without drawing a drop of blood. His man card is revoked.
Simon is Rick's equal in being a posturing douche bag.. Walking into the ambush was dumbassery. And who was idiotic enough to not think some of the wounded would die and turn? Hell, the series is titled "Walking Dead". Duh. Also, I hate spook shows with kids. They always screw up and get everyone killed but themselves.