Thoughts on how this is done? Pop Up Tray

spring loaded or pressurized cylinders on each side, she probably moves a lockdown pin on the box to pop it open. The cylinders look like what is on vehicle back trunk or front hood (maybe smaller) - believe they are called rear hatch struts or tailgate lift supports.

Looks to me that it's just spring loaded. If you notice, she gives the table a quick upward jerk to flip the lid. The springs are probably installed in a way that keeps slight pressure downward on the lid when it's closed but as soon as the lid is slightly raised it forces the lid up.