Key points to take note are that the zig zags are just 1/8th motions.

Listen to the music to help you keep pace with the slower flick notes to avoid breaking by going too fast.

Most importantly, the exit for the 2nd zig zag pattern ends with slower flicks so you need to manage the transition from zig-zag into slow slide well.

The alternative to the double 3 note flick sequence is to use the same thumb for both (making a quick re-position to continue sliding) This method is a lot more vulnerable to giving Greats as it requires the player to quickly adjust between fast and slow hand motions