First of all you get the evidence that the tadpoles are altered quite soon. Because with normal tadpoles you're supposed to have some nasty symptoms on day 1. And you, all companions and some NPC acknowledge that you didn't get a single symptom.
Second you get a tip that Lae'zel solution maybe a trap right after getting the direction towards the Gith patrol. In addition if you try to get more details from her and listen to some background conversations between her and Shadowheart you will get more reasons to feel worried about how grave her solution may be.
