You whip out your sonic screwdriver and aim it at the heavy metal door, swiftly unlocking it and hitting the Dalek as it swings open.
Unfortunately, the tinpot terror is still between you and freedom, and it’s sustained no damage by being hit by a door. Of course it hasn’t – it’s a Dalek.
And even more unfortunately, another Dalek has heard the commotion and made its way into the room, knocking over the cleaning bucket on its way in and making a slippery mess on the floor.
Now there are two Daleks between you and the open door. What do you do?