"...This spell takes no time to cast, and..."
Using this item in battle clearly shows that a turn does pass when using it. People on the IRC informed me that it was because items always take a turn to use. However, the description is really misleading, so either that clause ought to be deleted or an exception ought to be made. (It's the TARDIS. It gets to cheat on normal rules about taking time

P.S. It wasn't till I wrote this forum subject until I realized the acronym joke.