No!!! You can't shoot zombies when others are in the same space. You end up shooting your teammates instead! Only melee weapons can be used at close range UNLESS you are the only one in the square.
BUT, since you had an extra action and found that bat, we can switch the order of your actions and still save the day by clubbing the walker to death! NICE JOB!
Thank-you for the !LUV, !BEER, WINE, !PIZZA, !LOLZ, !ENGAGE 25 and !HYPNO.