Yes, it's a bit vague. Here it basically means 'really fast growth'.

Technically it should refer to a geometric contraction; for example, if one 'step' occurs in 1 second, the next in 1/2 a second, the next in 1/4 of a second, and so on, as seems to be occuring at the moment, then the number of steps will tend to infinity as 2 seconds is approached. This seems unrealistic though; infinite growth is a physical impossibility.