Charles Spurgeon Commentary John 18:17-18

"The maid therefore that kept the door saith unto Peter, Art thou also [one] of this man`s disciples? He saith, I am not. Now the servants and the officers were standing [there], having made a fire of coals; for it was cold; and they were warming themselves: and Peter also was with them, standing and warming himself." — John 18:17-18 (ASV)

Then saith the damsel that kept the door unto Peter, Art not thou also one of this man's disciples? He saith, I am not. And the servants and officers stood there, who had made a fire of coals; for it was cold: and they warmed themselves: and Peter stood with them, and warmed himself.

That was a very dangerous place for Peter to be in; he would have been safer out in the cold.