The logic in E1B is the same as in Fenix (and many other lights), but Surefire is using a forward clickie and like Fenix it has no memory.
I.e.:
A full press: Turn on in high
A half press and then a full press: Turn on in low mode, with a flash of high first.
When on in high mode: Two full presses to get into low mode, with a short darkness between.
When on in low mode: Two full presses to get into high mode, with a short darkness between.