Lets also notice that we have two meaningful jumps between frames, from 5:04:27 (on the camera time) we see like ufo came out from the vulcano, and next frame is 5:04:57.
It can has two meanings:
1. according to previously estimation that it is about 270m long, it pass about it's long distance (270m) in a 30s. That means it's velocity was only 9m/s.
2. We dont know what happened between 27 and 57 seconds of video so we lack an information about how many of them came out o_0