Wait a minute...is this a plot-hole (Austerities of Wind and Main Scenario-related)?

[Samcaesar]

We know after all that summing more than an Egi via the allagan method WILL kill us.

Wait, can you tell tell me where we learn this? I thought we summoned an Egi simply because it's controllable, just the pure essence of the primal so that it takes a manifestation of it, albeit smaller, and doesn't have the personality most primals have?