Some things in this make no sense.
Why wouldn't you burn the building down where the hive of zombies were located? The guy did say something about them dispersing which is why he was against it....But that makes absolutely no sense since they would be dispersed into daylight. They do remember day light kills them?
Everyone at the police station is suspicious when Thomas arrives.Which is a valid concern.However, their reasons are hilarious. Its a scam! A trick! Yes the whole plot that Thomas's marauder group agreed to was him shooting them all dead and leaving one behind bleeding to be killed alive by zombies...Just to trick Sam..Good Job guys! You can get back up now!..Oh wait.
Thomas and the SWAT members couldn't be bothered to notice the Alpha zombie was wearing Kevlar..Not like it was subtle or anything.
SWAT guy near the end locks a zombie in the cell.What do you do? Toss and waste a grenade to kill one zombie in a locked cell..Makes sense.
Building full of cell doors and none of them are actually strategically used. There where a couple set of doors that would have completely stop the zombies from proceeding any further..Quite literally no one had to die If they used common sense.