This is a little late, but i just read this now.
First of all i want to let you know that FIRST students really care about their mentors, hence i want to thankyou for putting your heart and soul into us although you are sick. I dont know you, but i respect you like i do my own mentors. This incident is unacceptable; however, i am not sure how this could be prevented. I guess some people think that idiotic pranks like these are funny. I do hope deep down in my heart that this wasnt someone involved in FIRST, because i would like to think that we are better than this.
I am glad that you are fine and nothing serious happened to your health.
I think as a FIRST community we should be on a lookout for such incidents and stop them. We can start at our team and make sure that everyone realises their behavioral responsibility. And when we go to a regional we should all look out for someone trying to pull silly pranks.