1. WHEN SAM ENCOUNTERS THE TEST CARD GIRL
This isn't really a single moment, so much as a whole strand of strangeness which follows our hero as he tries to stay sane in the 70s. Just who is the Test Card Girl? She seems to be a physical incarnation of the iconic girl from Test Card F. If you're too young to remember, Test Card F was a still image which would be used to fill dead air on television, back in the days when shows weren't on 24/7.
The image was strangely cryptic, featuring a little girl in a red dress apparently playing knots-and-crossed with a strangely sinister clown doll. Which is weird in itself, but nowhere near as weird as the little girl turning up to taunt and haunt Sam when he least expects it. Is she a manifestation of the Grim Reaper? A demon from another dimension? Or just more evidence that Sam is going slowly bonkers?
2. WHEN SAM MEETS HIS OWN MUM
The thing about going back in time to the 70s is that Sam has been here before, when it was the 70s the first time round. And that means he can revisit places from his childhood, and swoon with nostalgia. After having strangely vivid dreams of his old home, Sam decides to throw caution to the wind and go back there - at which point he comes face to face with his own mum, who at this point is still a young woman. Adding to the weirdness, she mentions little Sammy, who's apparently ill with the mumps. And as if this isn't enough of a shiver-making moment, Sam will later encounter his own father too.
3. WHEN SAM EAVESDROPS ON HIS OWN FUTURE
When he wakes up in the 70s, Sam can't quite believe what's happening to him. So he acts like any reasonable person, and tries to get hold of a friend on the phone. Picking up the landline receiver in his office, he's surprised to hear the voice of an operator, who is quite aghast when Sam asks for a Virgin Mobile number. "Don't start that sexy business with me young man, I can trace this call," she says, hanging up.
At which point Sam suddenly hears the jolting, electric zapping noise of defibrillator, and the sound of someone - a paramedic, a doctor? - calling his name. Is it the sound of the real Sam in the real world, after his accident? And if he can hear it, why can't he hurry up and WAKE UP?
4. WHEN THE OPEN UNIVERSITY TALKS TO HIM
Once upon a time, one of the most cherished/parodied aspects of British culture was late night educational programmes by the Open University. In the 70s, these usually featured men with a big beards and NHS specs, standing in beige rooms and droning on about equations, electromagnetism or geographical faultlines.
During one of these 2am broadcasts, a bearded lecturer starts to casually discuss Sam's coma, and the level of his brain function. Sam immediately starts yelling and banging the telly, begging to be acknowledged. It seems to work. On the flickering black-and-white screen, the lecturer seems to look directly out at Sam... but it's to no avail. Sam remains trapped, and seemingly alone.
5. WHEN SAM GETS A CALL FROM THE FUTURE
One thing the coppers know how to do in the 70s is throw a good party. When Sam enters headquarters after one such shindig, he's met by the kind of utter chaos that would have HR sacking the whole lot of them if it was the 21st Century. While surveying the merry devastation, Sam hears a phone ringing. A phone which has a severed cord, and therefore has no business ringing. Scary? Yes. And even scarier when he picks up the receiver and hears his mum telling him they're going to be switching his life support machine off. Yikes.
6. WHEN SAM'S NEWSPAPER CHANGES ITS MIND
While shaking down an informant with Gene Hunt, Sam chances upon a newsstand headline in the street, which reads "SAM TYLER: WE ARE SORRY FOR YOUR LOSS." By this point, Sam is almost used to sudden freakish moments like this, but even he is confused by what the message means.
Things become a little clearer (if that's the right word) when he picks up a newspaper and sees the front page literally change before his eyes. It appears to turn into a story from the future, telling him that a top cop has died. A top cop who happened to be Sam's greatest inspiration and mentor. This really can't bode well...