As Swain approached Johnson to ask him questions, the prime minister's press secretary can be heard cursing and then Johnson said, "I'll be with you in a second" as he retreated into a large refrigerator filled with milk bottles that he was helping to deliver in last-day campaigning.
The British PM was trying to avoid talking to a reporter from the Good Morning Britain programme.
"Prime Minister, will you deliver on your promise to come on Good Morning Britain?" the reporter asks again. Many criticized the prime minister's response to the media, calling him "cowardly" and "pathetic".
Swain asks the prime minister whether he would be interviewed on the show, which is presented by Piers Morgan and Susannah Reid, provoking a foul-mouthed reply from his press secretary: "Oh for f**k's sake." .
This election is Boris Johnson's to lose - the polls make a Conservative majority all but a certainty, even if the final-day betting odds see the chances of overall Conservative control falling from 79% to 69% overnight - meaning Conservative spin doctors have implemented a low-risk strategy.
But the PM ducked away while press aide Robert Oxley turned round and swore at Swain.
Mr Morgan and Ms Reid are heard expressing their shock on television before Mr Swain later says to Mr Oxley: "Do you want to tone your language down as well because people are watching this this morning".
But Wednesday's choreographed stunt got off to a bad start when Mr Johnson was doorstepped by the camera crew.
"I'll be with you in just a minute", Johnson said, before turning and walking into a giant fridge full of milk. "I've come here with a message of hope!" They remarked that Miliband was regularly accused of not being "tough enough" and so "what we need is a tough guy, a real strongman who'll hide in a fridge", like Johnson. But Johnson stays glued to his tour, lifts some milk crates, and eventually escapes into the fridge.
As of Wednesday morning, nearly 21,000 tweets have been shared with regards to the video, and the hashtag #fridgegate becoming the top trend in Britain.