He's as much a professional as most Gothamites.

Riddler lowers himself down, stretching his legs out and leaning back on his hands to look out over the buildings around them. "I might need a drink to start unravelling that. Simply put, he's Oswald from my Gotham, but... he's from five or six months further ahead than me. And when we met him, he seemed ready to try and stab me. He ate only when he was assured it wasn't poisoned and only managed to sleep when he could lock himself in my room and was gone when I woke up. Ed is... upset."