slowly, conservatively, with due precautions
defensively (part of speech: adverb)
vigilantly (part of speech: adverb)
cautiously (part of speech: adverb)
attentively (part of speech: adverb)
- " Governor," said Winnie cautiously putting her head out at the door, just as the summer dawn was growing into day, - " Governor! - "Hills of the Shatemuc", Susan Warner.
- Once I cautiously approached his hiding- place in the wall and waited. - "The Wit of a Duck and Other Papers", John Burroughs.
- The young girl opened her window cautiously, saw the note, took it, and stood before the window while she read it. - "Juana", Honore de Balzac.