Running against the crowd of people that is running towards you is not a good idea. But that's what Jon was doing. Most of the time he could keep going, but sometimes someone knocked him on the ground and caused him to find his bearings before he could get back up again.
Once most of the people were out of the way, Jon had a much clearer path to the whatever was making the rumbling sounds.
Part of him wondered if this was a good idea. These people probably had the right idea. Run away from the terrible noise, not towards it.
But something inside Jon made him want to go towards it.
It had only been about a minute, but it seemed like a lifetime. Jon finally turned the corner and saw ...