Reading the word "thanks" gets the corner of Marty's mouth tugging up, and he offers a thumbs up in lieu of writing something else. It's probably a better time saver, anyway.

It's more important to write: I don't know anything about snakes but I didn't wanna risk it being one of the bad ones
You think there's more of them here?

Having filled his space with writing, Marty switches to a new leaf, filling in a quick message at the top of it.

They might hurt someone else

Especially considering this is a very obvious workspace.