He will go straight for a tree that is taller than his. He might be smart enough to wait till your gone or not looking, or have no fear and just bolt for them. My first veiled, Stella, we took her outside and there was a bush right near by and she climbed down her tree very slow with one eye glued to us and as soon as she hit the ground she ran

Never seen a cham move so fast.
On the other hand. my two male veiled never seemed to care when outside. The tree they would bask in, was taller than me and there wasn't anything close enough for them to climb. So they would just chill.