In ‘The Bells of Saint John’ the Doctor demonstrates the abilities of the TARDIS to new companion Clara. Normally I’m of the opinion that the TARDIS should be used to transport characters to the adventure but this story provides numerous examples of how using it sparingly can help the heroes.
First of all the Doctor ‘hops’ the TARDIS on to an out of control plane, before it can crash. It would appear that the TARDIS dematerialised and travelled through the vortex in space but not time (as opposed to flying the TARDIS into the plane in the physical world).
This is an example of the TARDIS being used to get into a physical space that would otherwise be impossible or at least very difficult for the player characters to reach without it.
This can be invaluable when the adventure requires them to reach a specific destination without requiring them to breach security, overcome obstacles that stand in their way or spend time getting there.
Here the Doctor needed to get on to the plane and the only way to do that given the circumstances was to use the TARDIS. Similarly the PCs might need to get into a prison or a ship at sea quickly.
To stop this from being abused the player characters will have to meet the following requirements. Firstly they need to know where their destination is. In our example above they’d need to know where the ship was to materialise on board.
Secondly the TARDIS can only be given a rough location to land. For example they might appear in the aliens secret base but not in the control room. This means they’ll still have to explore their new location to find what they want.
Using the TARDIS to ferry player characters can save time but also puts the ship in a hazardous location. If they take it behind enemy lines there is always the possibility that it will be captured and if they take it on a vehicle or craft it could be lost should that location crash.
Next the Doctor takes the TARDIS to the following morning. Normally the Doctor is reluctant to leave once he is on the flow of events but it is very possible that moving forward in time a short distance has less risks. After all, as the Doctor says, they are only taking a short cut. They would have reached the next morning eventually, the TARDIS just makes sure they reach there more quickly.
The reason the Doctor does this is that he wants their opponents to tire themselves out searching for them while they, in theory, are more rested. This can be a handy tactic for player characters who are being pursued.
During the time they skip over they will be impossible to find because they don’t exist. Coupled with the TARDIS’ ability to take them to a new location pursuers will find it very difficult to pick up their trail.
You may wish to represent the effects of fatigue. If characters spend extended period without rest they should suffer a negative modifier to their rolls. Players can take this into account and use this tactic to ensure that their enemy is more fatigued than they are.
This only applies to opponents who go without rest (so they must have reason to keep active, such as searching for the player characters) and those who suffer from exhaustion. It is entirely possible a Cyberman could continue searching for days without rest.
This tactic can backfire if the opponents use that time wisely. If they are working to a schedule the player characters might emerge from their TARDIS to find that their enemies are further along in their plan without the player characters presence to distract them.
There is also a danger that they might skip more time than they planned. They might find that they didn’t arrive in the morning but in early afternoon or even a week later. Going back now would only complicate things.
The final use of the TARDIS (although we don’t see this in full until the next episode) is that it can give you more time. Between the Doctor leaving Clara and picking up her up the next day (from her perspective) he has had time to explore large sections of her timeline.
The Doctor Who books and audios have also made use of this function, allowing the Doctor to carry out research, do some ironing, rest and recuperate all while very little time passes for those outside the TARDIS.
Players should only be allowed to do this when it speeds things up for the plot. If the player characters really need to build a specific gadget for an adventure they can spend weeks assembling it within the TARDIS and re-emerge only minutes later from the perspective of an outsider rather than forcing things to drag to a halt while everyone waits for them to make it in real time.
Similarly if a character is incapacitated they can go through the whole healing process off-screen in the TARDIS and re-join the group for the rest of the adventure, rather than forcing them to sit things out.
At the very least using the TARDIS in this manner should require the use of a story point. The longer the players want their characters to have within the TARDIS the more points it should cost.
In addition, while the Doctor has a long enough lifespan to spend as long as he likes outside normal time, his more human companions will soon show the signs of aging. They might also get very bored and more than a little stir crazy if they have to stay in a TARDIS for weeks or months on end.
These tactics should always be used to serve the plot and keep things fun, rather than give the players a way to give their characters an unfair advantage or remove any urgency from the adventure.