[calmon]

I did some tests some time ago.

11 Astral isn't enough. You need 12.

With 11 Astral you end up with 114 fatigue (with 0 spell casting encumbrance)

With 12 Astral you end up with 88 fatigue.

The formular is something like 800/(spell bonus + extra gems + 1)

So if you have 11 astral you can use 11 gems which gives you 3 extra gems and 3 spell bonus:
800/(3 + 3 + 1)= 114

With 12 astral you got 800/(4+4+1) = 88 which is enough for teleport out.

You can always teleport another commander in and set your enslaver something like:
Enslave/Returning/Returning/Returning/Returning (eg with 114 fatigue)