It is possible to restructure a TARDIS so that it can be "materialized" within the conscious (or unconscious) mind of a sentient being - including the mind of the Time Lord who is symbiotically linked with it. This is possible because a TARDIS is not composed of real matter but collections of Block-Transfer Equations. Piloting a TARDIS into its operator's Dreamtime is very difficult and dangerous for both the TARDIS and the operator and will result in severe damage to the TARDIS.