Security Protocol 724

From Tardis Wiki, the free Doctor Who reference

Security Protocol 724 was a security feature aboard the Doctor's TARDIS which was meant to warn Gabby Gonzalez, though it ended up warning Cindy Wu, that the TARDIS was under attack and the dimensional stability could be compromised. After this warning, the Security Protocol, which displayed a holographic projection of the Tenth Doctor, suggested the companion to exit the ship. (COMIC: Old Girl)