Could mean a lot of things. Do not presume explosions.
I was on an MD-88 on a take off roll in Greenville, SC when the port engine went pop-pop-pop, bang bang bang. Scared the crap out of all of us. Seems a strong cross wind contributed to it, according to the pilot. He tried the same runway one more time (with cross wind, but longer length). Same result, not as bad. Then he changed runways without incident. Some fun.