The servants and officers had made a charcoal fire, because it was cold, and were standing there and warming (ethermainonto | ἐθερμαίνοντο | imperf mid ind 3 pl) themselves, and Peter also was standing with them and warming (thermainomenos | θερμαινόμενος | pres mid ptcp nom sg masc) himself.
Reference
John 18:18
Sequence
3