It didn’t look like a police box when he stole it. It looked like a silver capsule.Now, we know Dr.1 stole that TARDIS, but it was in repair bay and the chameleon circuit failure could have been already in effect at the time, and manifested as the last disguise it used when he initialised it.
You’re all wrong. The tardis stole a timelord to explore all space and time.Clearly Hartnell-Doctor stole the TARDIS, but I suppose there could have been a Doctor before him who used one, but officially rather than unofficially....?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.