So if I read you right, this should (by pressing the same key) cycle through either all 4 locks fears one at a time until the first one is up or 40 seconds has passed?
Exactly! For Every hotkey press, the macro moves to the command after the comma.

eg /castsequence reset=target/combat Curse of Agony, Corruption, Siphon Life, Immolation

I use this on my Number 3 key, an everytime I press it, it casts each spell in turn before Cycling back to the start.
First Press: CoA
Second Time: Corruption
Third Time: Siphon Life
Forth Time: Immolation
Fifth Time: CoA
etc etc.