Well, based on the fact that Heaven Sent is the worst Doctor Who story of all time, anything would beat it in this kind of poll. Even the Gunfighters is better.

Heaven Sent is an unremmitting onslaught of overblown, self-obsessed pomposity; Moffat at his self-indulgent worst. The Doctor spends four and a half billion years punching his way through a giant diamond to escape his own conscience, all the while dying each night only to be reborn each morning like an ancient sun god. It's too ridiculous for words.

@Falkirkdouglas That really made me smile. I like Heaven Sent in its context, but it's mainly due to Peter Capaldi being so good. I think parts of it are absolutely sensational, but it's very close to not being Doctor Who at all. Best episode ever, as voted in DWM, is frankly insane.

I prefer Midnight either way.

Can I ask the OP what’s the connection between the episodes

I wouldn't be too sure... I have watched Midnight on BBC iPlayer, but I probably watched Heaven Sent when it first aired eight years ago.

Midnight, by ten country miles.

Heaven Sent is great but certainly overrated in some areas of the Doctor Who palaces.

I’d pick Midnight over any episode

I guess it depends on what type of psychology you find more interesting. For me, Midnight without a doubt.

Heaven Sent is my favourite episode because it has more depth than your average Doctor Who episode.

It works as an allegory for grief and I think the the underlying themes of the Doctor’s misery and him growing tired of losing people work perfectly here to create possibly the best look we will ever get into the Doctor’s psyche. It doesn’t shove the metaphor in your face unlike some other DW episodes (Ahem, CHIBNALL!) and I just love everything about it.

Also Peter Capaldi is always a plus.