iControl Server Thread Safe ?

I developed an application that allows the user to toggle the state of a pool member (or pool members).

 

 

The use case: a pool might have 10 pool members, and 9 or the 10 are enabled. Now, I want to enable the 10th pool member, but before I can do that, I need to disable the other 9 (this is one of our internal requirements). The call to disable the 9 pool members was handled by about 5-8 threads. What I was noticing is that when 2 of the threads sent the soap requests to the F5 at the same exact time (same millisecond), only one succeeded, and the other one was simply ignored (no exceptions, no changes).