Hamilton had owned a postcard of a Berlin hotel lobby for many years before he began working on a painting based on the image. He saw the lobby as a somewhat impersonal and claustrophobic space: I have been moved to say that Lobby is an old mans picture; the atmosphere is certainly none too cheery. Hamilton compared his painting to Jean-Paul Sartres play Huis Clos, which he said was a metaphor for purgatory, the limbo in which we await transit to another condition.
He also wanted to make a painting of an interior that, while mundane, was spatially complex. With his longstanding interest in perspective systems, Hamilton developed a work with several vanishing points, thanks to the reflections of the space in two planes of a mirrored column. The inclusion of two flights of stairs made the space more perplexing still.
Having completed the painting in 1987, Hamilton showed it in 1988 in Edinburgh, creating an installation to double the depicted space, complete with stairs, the column, and the dotted carpet. Like Treatment room, this somewhat disorienting environment stands in contrast to the playful installation of his 1956 Fun House.