Large text entry boxes - what's expected behaviour?

I have a text entry box that learners will write a large amount of text in - more than can fit onto one slide. The text entry box correctly fills up as learners type more text and the focus shifts down the box. You can use your mouse wheel to scroll back up the text or you can use the arrow keys on the keyboard.

What if a learner doesn't have a mouse wheel? Using the keyboard is clunky to say the least, so I tried add the text entry box to a scrolling panel, but because the text entry box has its own inherent scrolling behaviour, the scrolling panel never activates itself because it doesn't recognise that the limits of the object within it have been reached.

Is that how it is supposed to work? Am I missing something?