Imagine a circle with radius of 120 pixels. In the centre of the circle is a square cursor (10x10pixels). every 0.02 seconds the cursor's position moves on both the x and y axis a random amount of pixels (mean = 0 standard deviation = 3).

What is the probability over time that the cursor will exit the circle?

I have simulated this and derived the probability that way, but would really like to know if there's a better way to determine the probability of exit for a given amount of time-elapsed.

Thanks for your help!