Basically, there decided that they would not risk running through the ice in the middle of the night. In fact, they sent there infamous "Stopped in Ice message" to the Titanic earlier in the night. This was the same message that prompted the Titanics wireless operators to respond with "Shut Up, Shut Up, I am working Cape Race". Survivor testimony stated that by time dawn broke they saw numerous icebergs, "growlers", and expansive field ice. The Californian was being cautious, with good reason.
Respectfully,
Andrew