If there's one thing symbiotes hate almost as much as sonics, it's fire. They come from the Frankenstein's monster school of thought on that topic, and it's very obvious in the way that tendrils suddenly sprout off his costume, waving madly. While it's not actually said, the 'OH SHIT' is very heavily implied.

Venom decides to scuttle for the relative safety of the house's side, trying to figure out his next best plan of attack.