Variables - the bane of my existence

I have a slide with 1 layer:

0. Base slide

1. Slide layer 1

On base slide, clicking a box takes them to layer 1.

On layer 1, I want learner to read some text, then click 'button2lightbox' that takes them to a lightbox. When they close the lightbox, they are back at layer 1.

Then, I want the 'button2lightbox' to go away, and a close button to appear that on click returns learner to the base slide.

Does this require variables? I tried controlling this through the timeline, by ending the 'button2lightbox' at the same time as starting the close button. But this doesn't take into account how long a learner will read the text on this layer. If they take too long, the button to lightbox goes away too soon.