Zaire, admitting its troops in the refugee camps were "out of control," said it would withdraw about 400 soldiers who have been pilfering Rwandan refugees' food and possessions in the border town of Goma. Thousands of Rwandans in the Goma camps protested Thursday against the soldiers, many of whom were unpaid for months and went AWOL to Goma to seek their fortune. About 60 miles to the south today, some 50,000 people reportedly massed across the border from the Zairian city of Bukavu, underscoring relief workers' fears of a new exodus when French troops leave southwest Rwanda in 10 days.RETURN OF THE KING? King Kigeli V. Ndahindurwa, who has not seen his country in more than 30 years, wants to go back to Rwanda now that his Tutsi tribe is calling the shots. The ex-monarch, who was deposed in 1961 when Rwanda became independent, has just relayed a message to the Kigali government, promising to let the people decide whether he should rule if he's granted entry. For now, King Kigeli, 58, lives in the Washington suburb of Takoma Park, Maryland. A recent report said the impoverished king had applied for food stamps there.