It's lunchtime and actors and crew are milling around inside. Without the amplified gloss, the lights, the polish, it's hard to tell them apart.
Outside, Malmholt gesticulates and talks very fast - a distinct advantage, one imagines, for a scriptwriter on a very fast turnaround daily soap.
(Zoom to Nick): " You have to be aware of your audience and your broadcaster, but all we're doing is trying to tell stories through the words and interactions of our characters as truthfully and urgently and entertainingly as possible, and so the language is always character specific.
"And that is pretty much it. You're listening to the characters as you go, and their words emerge."
As Shortland Street has evolved over a quarter of a century, so too has the language that has breathed life into characters and storylines and given them warmth, wit and humanity.
Malmholt, who began his career as a television journalist, has written dialogue for the show for most of that time. He sharpened his skills on Coronation Street, arguably the gold-standard of soaps, before returning home to the other "street".
"What was great about Coro Street is that you could see the symbiosis in action there. The story, the scripting and the production had a sense of each other and real-time improvement, from the story's inception. It was a beautifully and well-oiled machine with a rich deep literary and showbiz background in the North of England."
(Cue: bang table): "But Shortland Street has something similar - it's New Zealand-centric. As a writer, you are aware of the great shows that elevate storytelling and they have new techniques for achieving emotional impact. But you can't compete with other storytellers because your first reference point has to be people and the world and then New Zealanders.
"Whether cast, producers, writers - we were always trying to elevate it and make it become the theatre of the nation. And it did."
There's always been a desire, he says, to transcend the limitations of soap.
You can test, but you cannot, however, transcend the limitations of censorship. Particularly for a 7pm, week-night show.
"Every now and then there'll be a word we can't get across, or we've used it a few too many times. And then we have to adjust in the edit so we don't inflame or distress or give a sense that the show is off balance.
"We try to not do gratuitious. If it feels that way it is gratuitious. (Bang).
"You're aware of the audience. You have to be. But it's beholden on us to push boundaries. If the idea or the exchange is fresh and urgent and emotionally dangerous and original - it's going to get some people's backs up. You don't want to shy away from pushing the boundaries of feelings. Or making characters uncomfortable and your audience uncomfortable because there lies the beauty and utility of drama.
"We have to listen to the audience. We don't want people turning away -- we want people uncomfortably leaning in."
Uncomfortably leaning away was what many viewers mostly did back in the early days.
It had a lot to do with hearing our language bounce back to us. But, says Malmholt, the cringe days are gone.
"It no longer exists but it was very much in the minds of the first writers and viewers. Everyone watched Shortland Street with an anticipation of embarrassment and failure. Within just one or two years Shortland Street had banished that. Particularly the younger viewers were really open to hearing the Kiwi vernacular.
"So rather than looking at overly dramatic or awkwardly constructed visions of themselves, they were literally seeing themselves, and the words they were speaking were just one small part of that sense of truth and ease ... "
Delivering that truth in a bankable way for 25 years requires drawing on instinct and craft.
"When you're first writing or doing your first draft - all you're doing is just pouring our what you feel - you're being the characters, listening to the characters, and it's all happening in a spontaneous way. But then you have to step back at it and look at it again. That's when you apply whatever techniques of analysis or intellectual second guessing or deconstruction, you read it dispassionately. And you say, is this really working?
"That's when you become quite ruthless and sharpen or amplify or have it make more sense - it's a combination of inspiration and spontaneity checked by technique and rigour."
(Margin notes to budding scriptwriters: develop a tough outer layer): "You cannot take personally any criticism. Sometimes you think, 'well if they don't love my work they don't love me'. That's just a normal human response but it's not about that. But if you are going to bring that ego or that egocentric emotionalism into what should be a dispassionate and enthusiastic workshopping that is about making something better, then f*** off.
"Yes you do get hurt. All the writers are pouring their heart and guts out to get a response from the cast or the directors or the audience. When that doesn't work, it can hurt. But you have to be an adult, and grow up and try something that does work. Simple as that.
"The first thing is you can't let the perfect be the enemy of the good. You always have to improve, improve, improve but you have to stop - you have to meet the deadline - you never reach perfection. You have to reach a point where you're happy enough to hand it over to the next stage - the producer and the director, because you have to move on to the next one."
This is not life and death, but television. But there is death - often brutal, gory and sometimes ludicrous, on Shortland Street. When a character dies, is this a failure of the writing?
"If a character hasn't worked it's our fault - it's that simple. Obviously it's a combination of writing, casting and directing - if you get the casting right and the writing right, and it's directed with generosity and clarity and sympathy and compassion you've got gold. Sometimes, one of those three things go wrong.
"Fundamentally I believe you can write your way out of any hole if you try hard enough. But some characters are not killed off because they fail - it's because that is where the story will go most powerfully. Because death is part of life. Not every character exit is a failure. Sometimes it's a dramatic, triumphant and edifying end.
Some will be shuffled off because we haven't managed to make it work."
Twenty-five years is something of which to be justifiably proud. But if Shortland Street was pitched now, says Malmholt, it wouldn't work. "If you look at the history of the launching of daily drama round the world in the past 15 years it's not happening. The shows that are most similar - as a mode for getting eyes on screens - are not happening. What broadcasters are committing to are versions of telenovella. 'We don't want to commit to 5000 eps but maybe 100'. I don't think you could get across the line an open-ended soap."
So given how familiar, and successful the show is, would anyone dare pull it?
"Of course they would. You can't take anything for granted. You have to be earning every audience member. Fight for their trust and take nothing for granted. Do I think they would be fools to cancel it? Of course I do - that would be a terrible mistake. However, TV networks have been known to make mistakes in the past. There is no guarantee.
"It's a never-ending conveyor belt. Well, hopefully never ending."
(Lights fade).