Mavic Chen's Transmitter Beacon (Mouse-Containing)

The transmitter beacon containing mice is the linchpin of this event, serving as both a clue and a fatal liability. Initially, it follows the group through cellular dissemination, unnoticed but actively broadcasting their location back to Earth. The Doctor identifies it as the source of their exposure to Mavic Chen and, by extension, the Daleks. When Dalek 1 and Dalek 2 detect its signal, they destroy it in a burst of fire, silencing the transmission and scattering the mice. The beacon's destruction marks the point of no return: the Daleks now know the group's exact location, and the fugitives' refuge is compromised. Its role is dual-edged—first as a tool of betrayal, then as a catalyst for the Daleks' relentless pursuit.

The mouse beacon transmitter capsule is the critical object in this event, serving as both a lifeline and a betrayal for the Doctor, Steven, and Sara. Initially, it follows them through cellular dissemination, pulsing signals back to Earth that the Doctor believes Mavic Chen will use to locate them. When the Daleks detect its signals, they identify it as an alien device and destroy it, obliterating the fugitives' last connection to Earth. The destruction of the beacon marks a turning point, severing their hope of rescue and exposing them to the Daleks' relentless pursuit. Its role is pivotal in raising the stakes and introducing the immediate threat of the Daleks' indiscriminate attacks.