When hackers/IT people in a movie have a fully mobilzed datacetner/networking/rack gear they've seemingly configured in a matter of minutes or hours, not days or weeks. Forget stabilizing custom software, too. It just works. AND you can hack any protocol with it!
When hackers/IT people in a movie work in a room that has a bunch of server racks blinking away and it's not 90db of whirring fan noise. Datacenters are LOUD.
And it would be so hot as well. Server racks expel uncomfortable heat. Without an industrial sized HVAC system your improvised datacenter would become a sauna in a matter of minutes. There's a reason datacenter would be a warehouse sized fridge if it wasn't for the extreme heat that the server racks output. You need thick coats to enter those places for how cold they are, but only because they're battling the heat from all those chips and other electronics.