Doctor Who just announced a worldwide publicity tour. Is this because Peter Capaldi is a former rock star? Then we introduce a brand new segment called “What If?” What if David Tenannt had stuck around for season five? Would the show have been different? Would 10 have flirted with Amy? How would River fit in? And what does Steven Moffat have to say about all this? In the second half, we check in on two episodes that celebrate the best of humanity—in roundabout ways. Caroline defends the oft-maligned “Gridlock” while Alasdair celebrates the guest cast of “A Town Called Mercy.”