A children's hospital has all the same drugs that an ordinary hospital does, although the individual doses are smaller. Also the needles and syringes but smaller sizes--all this could keep junkies happy for days. Add to that all those sharp scalpels for cutting up people these goons could have a field day in any kind of hospital.
You almost hope if they break in they steal the wrong drugs and ending up seriously hurting themselves. There are paralitics and othe such drugs which can kill you in seconds, also many drugs need to be diluted before injecting them.