Na verdade, vemos isso em " Listen ", onde a TARDIS é aberta embaixo d'água. Com todos os seus sistemas funcionando corretamente, ele simplesmente fica preso dentro de sua própria bolha de ar com a água mantida a uma distância segura do lado de fora.
Sobre como isso é alcançado; no episódio " Logopolis " há um longa discussão do plano do médico para abrir as portas TARDIS debaixo d'água. Desta conversa podemos deduzir dois fatos principais:
Um número substancial de sistemas precisa ser desligado para permitir que a água entre pelas portas
∴ Em circunstâncias normais, as portas podem ser abertas sem sofrer um influxo catastrófico de água
DOCTOR: No, how can we with the Master in the Tardis? They're a retiring people. They like a quiet life. There's no telling what a creature like that would do on Logopolis.
ADRIC: So how do we flush him out?
DOCTOR: And there's no saying what that might do to the Tardis systems. Can you swim?
ADRIC: Yes.
DOCTOR: Good. Materialise the Tardis underwater and open the door.
(Down in the Cloister Room, Tegan walks round the police box. The door opens invitingly. The Doctor calls up an aerial view of London on the scanner.)DOCTOR: That's the River Thames. We'll put down there.
ADRIC: And water sluices in and floods out the whole Tardis.
DOCTOR: Yes. Adric, shut down everything. Fold back the Omega configuration. (Adric gets on the floor underneath the console.)
ADRIC: Folded back.
DOCTOR: Good. Exponential cross-field?
ADRIC: Halted.
DOCTOR: Good. Pathways to conditional states seven to seventeen?
ADRIC: Closed.
DOCTOR: Excellent. Main and auxiliary drive?
ADRIC: Ended.
DOCTOR: Good. Now, we're partially materialised, so there'll be a slight jolt. Are you ready? ADRIC: If you are.
DOCTOR: What? Well, I'd feel more confident if you just said yes.
ADRIC: Yes.
DOCTOR: Good. Here we go, then.[Cloister room] (Tegan gets jolted.)
TEGAN: This is too much!
[Tardis]
DOCTOR: A gentle splash-down.
(Thud! They fall to the floor.)
DOCTOR: We must have touched bottom.
ADRIC: Touched bottom?
DOCTOR: Yes. Good thing the water was there to break our fall.[Cloister room]
TEGAN: Crazy idiot of a pilot! Wait till I have a word with him.
(Laughter comes from the open door of the police box.)
TEGAN: Who's that?[Tardis]
(The Doctor is standing braced across the doors.)
DOCTOR: Careful, now. The water pressure could send us both flying. Ready?
ADRIC: Yes.
DOCTOR: Now!
(Adric presses a button and runs to join the Doctor. The doors do not move.)DOCTOR: That's odd. There's no pressure on those doors at all.
ADRIC: Perhaps we aren't down very deep. (The doors swing open and they step outside [onto dry land])