Take an interval. Cut it into H pieces, where H is hyperfinite. This serves as the index set of a stochastic process, among many other uses. Imagine that for each of the H steps, you flip a coin to get -1 or +1. Then move an infinitesimal distance left or right based on the sign. This is Brownian motion. Each infinitesimal piece of the timeline is profitably thought of as a Planck time.
Discrete events, such as sudden hard shocks, can be modeled on this line. They are appreciable over an infinitesimal fraction of the line.
Was being deliberately inaccurate here. Hard does mean more than a limited multiplier. Sudden means that there's an appreciable change over an infinitesimal variation aka discontinuous.
Lookup overflow, underflow, and "principle of permanence" in Goldblatt for why I'd do that. Also called overspill and underspill. The basic idea is "as above, so below" except this link is 2 way. Say some internal function has all infinitesimals in its range. Then it must have non infinitesimals too, since the set of all infinitesimals is known to be external, and images of internal functions over internal sets are internal. This is an example of overspill. Infinitesimal behavior has spilled over into the appreciable domain.
"as above, so below" tends to be two way, atleast outside of mathematics.