Doctor Who
S20E10
· Mawdryn Undead Part 2

Transmat explosion hurls Doctor and Turlough into chaos

The Doctor hastily opens the transmat control unit aboard the malfunctioning TARDIS, believing he can stabilize the failing system. His confidence proves misplaced as the unit erupts in a violent explosion, blasting him and Turlough backward with concussive force. The stumble changes their trajectory, disrupting both time and space as the TARDIS registers the massive temporal ripple. This catastrophic failure forces the craft off course and strands them in 1983, setting in motion a chain of events where the Doctor must rely on old allies and question new foes to piece together what has happened. key_dialogue: [ DOCTOR: Done it. ]

Plot Beats

The narrative micro-steps within this event

1

The Doctor successfully opens the transmat control unit, but it immediately explodes, throwing him and Turlough backwards.

anticipation to shock

Who Was There

Characters present in this moment

2
The Fifth Doctor
Time Lord
 primary

Tense resolution masking rueful acceptance of failure

The Doctor forcefully opens the transmat control unit despite the device sparking and failing, then endures the violent explosion firsthand. He is thrown backward by the concussive blast while retaining enough presence of mind to comment on completing the task.

Goals in this moment
  • • stabilize the transmat system quickly
  • • minimize damage to the TARDIS and companions
Active beliefs
  • • technical problems can be solved by rapid intervention
  • • even catastrophic failures are surmountable with ingenuity
Character traits
reckless pragmatism concise under pressure immediate damage control
Follow The Fifth …'s journey
Supporting 1
Turlough
Schoolboy
 secondary

Surprise overtaken by primal caution

Turlough is caught in the explosion and thrown backward alongside the Doctor. His shock manifests in dropping a small stone he had been holding, while his body reacts instinctively to the sudden concussive force.

Goals in this moment
  • • maintain balance and avoid further injury
  • • observe and evaluate the Doctor's next actions
Active beliefs
  • • clinging to the Doctor offers survival value
  • • any sudden disruption could escalate danger
Character traits
startled reaction physical instability loss of fine motor control
Follow Turlough's journey

Objects Involved

Significant items in this scene

1
TARDIS Transmat Control Panel

The Doctor retrieves the ornate transmat control unit and pries it open with hasty precision, triggering its self-destruct sequence. The unit detonates violently, launching the Doctor and Turlough backward while disrupting the TARDIS's temporal integrity. After the blast, the unit is presumably destroyed or rendered inoperative, though its residue lingers in the craft's systems.

Before: Intact and operational within the TARDIS console, albeit …
After: Destroyed by violent detonation, causing temporal stress to …
Before: Intact and operational within the TARDIS console, albeit failing under stress
After: Destroyed by violent detonation, causing temporal stress to the TARDIS

Location Details

Places and their significance in this event

1
Obelisk Hill Monument Site

Obelisk Hill's stark, windswept expanse becomes the backdrop for a sudden temporal rupture as the TARDIS materializes briefly before vanishing again. The transmat beam's destructive energy interacts with the obelisk's latent temporal resonance, amplifying the craft's off-course trajectory and embedding the disruption in the local spacetime.

Atmosphere Charged with latent temporal energy and the acrid scent of ozone
Function inadvertent temporal accelerator
Symbolism embodies the fragility of temporal boundaries
windswept granite hilltop sharp tang of ozone

Narrative Connections

How this event relates to others in the story

What this causes 1
Causal

"The transmat control unit explosion at Obelisk Hill (Act 1) directly causes the TARDIS to vanish and strands the Doctor in 1983, leading him to seek the Brigadier’s help (in 1983 Brigadier’s quarters) to resolve the temporal anomaly later in Act 2."

Doctor dodges identity question in sickbay confrontation
S20E10 · Mawdryn Undead Part 2

Themes This Exemplifies

Thematic resonance and meaning

The Unreliable Nature of Temporal Trust
5
Temporal displacement erodes the foundational assumptions of trust between allies and within systems. The Doctor’s faith in his ability to navigate time safely is challenged …

Part of Larger Arcs

The Doctor's battle to repair the TARDIS and stabilize the temporal anomaly caused by the transmat mishap, while dealing with his own disorientation and the loss of control over events.