One of the few mares working for Lamiňík, wasn't sure why she was send with a transport truck to dump the company's mutagenic goo into the lake, however she obeyed her orders.
The actual reason was an overeaction to a parasitic lifeform found in the lake, which could possibly be very contagious if not exterminated in some way. Though, this will slowly kill other things living in the lake as well. While the actual goo doesn't kill, the seer amount of it being dumped into the lake will displace the rather shallow water, not giving enough space to things living in their, including the oh so feared newly discovered parasite.