My office is a 12x12 room not including my closet. Assuming all 50 of those HID lights were in the kilowatt range, yes, either vertical or horizontal orientation of the bulbs would produce way too much light, and all but cacti would likely die off.

Even 170w of LED is burning my two large plants, and they're about 8 inches away from the panel. pH is fine, nute regimen is fine, plenty of air and CO2, both the same strain/genetics. The one on the right is closer and is burned more. I guess I'm going to have to use smaller hydro buckets next time.