The prisoners waited about a week for a moonless night, and on Friday 24 March, the escape attempt began. As night fell, those allocated a place moved to Hut 104. Unfortunately for the prisoners, the exit trap door of Harry was frozen solid and freeing it delayed the escape for an hour and a half. Then it was discovered that the tunnel had come up short of the nearby forest; at 10.30 p.m. the first man out emerged just short of the tree line close to a guard tower. (According to Alan Burgess, in his book "The Longest Tunnel," the tunnel reached the forest, as planned, but the first few trees were too sparse to provide adequate cover). As the temperature was below freezing and there was snow on the ground, a dark trail would be created by crawling to cover. To avoid being seen by the sentries, the escapes were reduced to about ten per hour, rather than the one every minute that had been planned. Word was eventually sent back that no-one issued with a number above 100 would be able to get away before daylight. As they would be shot if caught trying to return to their own barracks, these men changed back into their own uniforms and got some sleep. An air raid then caused the camp's (and the tunnel's) electric lighting to be shut down, slowing the escape even more. At around 1 a.m., the tunnel collapsed and had to be repaired.