Mount Rokatenda on the Indonesia island of Palue sent a cloud of ash two kilometres into the sky and was spewing rocks and lava on Saturday.
Petrus was one of at least six people injured.
He was caught in lava floods as he walked along the side of a river.
Search teams found him at his home and brought him to safety.
He's been taken to hospital for treatment
At least five people have been killed and two are still missing, feared dead.
More than 3, 000 people whose homes are within three kilometres of the crater were evacuated from their homes on Monday.
They're facing a stay in tents at this camp but others have not been so willing to flee their homes.
Authorities raised the warning status to high alert as the volcano became increasingly active last October.