The shelter behind the Ten Haaf family's house was known as 't Wilhelminahuis, because a portrait of Queen Wilhelmina was hanging there. Access was through the bike shed behind the house, where the dog Leo kept watch. Searches were conducted on the grounds of Dennenoord, but no one thought to open the hatch under Leo.  

It was by no means the only hiding place on the hospital grounds. Numerous people who had to stay out of the hands of the Germans were also given a safe place under the old laundry. Drawings and inscriptions still recall the voluntary confinement. A panel on the site points to the many other places where staff kept people hidden. This included in their own homes just outside the site.  

Food and other supplies were provided by an army of resistance fighters, all of whom lived by the motto that speaking is silver, but silence is duty. The motto was scratched into a bar at a hiding place, but applied to a great many Dennenoorders to a great extent. Plenty of weapons and voucher cards were also hidden there. 

Willem and Elsina were later awarded the Resistance Memorial Cross, but were initially suspected of colluding with the enemy because a large amount of metal was missing from his forge. Willem was even dismissed for mismanagement in 1949, but as early as 1945, an impressive list of former residents of 't Wilhelminahuis took out a newspaper advertisement to thank the couple.