Before the Master Dematerialization Switch is engaged, the TARDIS can be put in Pause-Control mode. In this mode the TARDIS will refrain from dematerialization even after the switch is engaged. Dematerialization will proceed automatically as soon as the Pause-Control is canceled. The control can be canceled by using the console to switch it off, or by inserting the TARDIS Key into the Locking Mechanism for 20 seconds. A Type 70a TARDIS has an improved Pause Control that can freeze a TARDIS in mid-rematerialization for up to 2 microspans. If a TARDIS is trapped in mid-materialization for too long, the chronometric particles being released from the event horizon will cause the TARDIS to "bleed to death."