They don't run away, the walls on the bottom are 35cm high and no branch reaches these walls. I haven't had any problems with runaways and the proximity of the lights is surely not a problem since these lights are not strong (uv and temperature wise). Room temperature is 18-20°C and local near the lamps/spots it goes from 22-25°C max. The advantage of keeping chams like this is that they can be much more active then in any enclosure, they also can freely choose between more moist spots (more to the bottem of the tree) and less moist (more to the top of the tree). The bottem consists of hydro grains, plant soil and moss). As you can see one side of the tree is exposed to the lights and the other side is the shade side. Another advantage is that when you mis the tree it feels like rain for the animals and keeps dripping for a significant amount of time. And yeah i can easily keep an eye on them, hehe.
best regards
Joery