But Beads, the OP does NOT state that there is "prep time". He states that either side can call some allies, not that they can do it in advance. And that side has to stay alive long enough to have that friend answer, have that friend decide to show, have that friend show up, have that friend decide to act, etc. Plus, since there is no location specified, it's Khazan, 100 feet apart.
Just going by Rumbles rules, yo. :-)