They're Using dye in Their IV, There.

 Teacher teacher

I declare 

You've misspelled 

There for their!

Students, they're so helpful!

This silly thought came to me. I am waiting for my sister to get out of surgery. They gave her green dye so they can look for gal stones...and I texted my husband because it is so interesting.  Except die is not the correct spelling and should never be used near an OR!