[Habibi Jones]

Hey guess what sm0ke, you cast it after you see them invis pot. How hard is it to go:
"Oh, they invis potted on that tile."
*Casts fire field scroll*

So yeah I'll insult you until you understand the concept, because clearly you don't understand that
1) Fire field scroll is faster than recall scroll
2) Given 1, you can easily cast a firefield scroll on the tile you saw them drink the potion on.