Forgotten author name, likely American or British – collection of short stories with sci-fi/horror-type themes. I read the book `eons ago’ – so probably 60s or 70s.
The story of interest describes where 3 characters wind up inside a room where there is “no time, only duration,” so they’ll supposedly live forever if they never leave the room. An epilogue then tells us “a building was torn down and 3 skeletons were found in it…..”
The cover had some odd-looking creature on it, reminiscent of the YELLOW SUBMARINE animation style.