Last Night: EastEnders, BBC1

So Stacey did it...but was Bradley pushed?

In most murder-mysteries you can usually safely assume that the killer knows who did it, even if nobody else does. But, until about 7.30 last night, even Archie's murderer was in the dark about EastEnders' biggest recent cliffhanger.

If you believe the BBC's publicity department, 10 possible denouements (or duff-duffs as aficionados know them) had been written and rehearsed. It was only within minutes of the first live broadcast of the soap – aired to celebrate its 25th anniversary – that the guilty party was finally tipped the wink.

Over the last few weeks, to the delight of the nation's bookies, the programme had assembled a supply of prime suspects that even Agatha Christie might have regarded as excessive, but in the end it was Stacey who tearfully coughed to the murder – shortly after seeing Bradley, the man she'd just married, plunge to his death off the Queen Vic's roof as the police closed in.

Bradley was as surprised as anyone, it seems. Seconds later, over on BBC Three, fake gore still dripping from his head, Charlie Clements (now taking offers) was having a microphone thrust under his nose for instant reaction on EastEnders Live: The Aftermath. "I didn't know ..." he stuttered when told that Stacey had turned herself in. "Was it? Blimey!" Who could blame him for not suspecting, though? If it's tough to be a vicar in Walford, with every wedding like a cross between a Millwall match and an unlicensed cage fight, it must be murder to be a CID detective: half the borough is tampering with the evidence or planting false leads, while the other half are grassing up anyone that's crossed them in the last week. And then half the people in the pub scatter like seagulls at the first flash of a blue light. It seems entirely possible that Bradley was pushed off the roof deliberately to provoke a guilty confession out of one the bystanders.

If you'd put money on them playing safe for the live broadcast you'd have lost it. Stunt work is hard enough at the best of times, but it's a lot more impressive if there's absolutely no chance to do a retake. And although there had been a couple of moments when the seams showed, it was only just – and only, in truth, because half the fun in watching was seeing if you could spot them.

Peggy, purple fascinators quivering above her head, had stumbled over an early line to Janine: "You keep on, June, with that silly story of yours", she said. On a normal day she'd have sworn, cracked a joke for the bloopers show and gone again. Last night she pressed on.

Jack Branning had given a couple of his lines a severe beating a little earlier, briefly threatening to derail completely but somehow managing to cling on to the cue. But that apart – and barring one small jostle of the camera as it all kicked off at the end – the episode was pretty much indistinguishable from a pre-record.

There were other revelations besides the name of Archie's killer – of incestuous rape, and undisclosed paternity. Dot Cotton revealed that she'd lied to little Dotty's mother, desperate for a second chance at motherhood. In other words, a typical evening in Walford – made unique only by the sense of occasion and of technological risk.

They'd dared to give Ian Beale a very cheeky line – following on from a scene in which he and Dot Cotton looked at an old videotape offering a little reminder of old favourites and old times: "Do you know what," he said wistfully, "I wish we could go back and do it all again. Do it right this time." It could have been a horrible hostage to fortune – but in the end they more than got away with it.