High performing plasmas are obtained in Optimized Shear(OS) configurations in JET due to formation of an internal transport barrier, with generally q(0) = 1.5-2. In conditions where sawteeth are stable, other MHD modes arise to limit performance. The most common is pressure driven internal kink mode coupled to the plasma edge [1,2]. The unstable dominant m = 2/n = 1 mode leads to an internal reconnection('crash') at the q = 2 surface. Some times the reconnection leads to a long-lived n = 1 island with rapidly decreasing frequency ('chirping' due to plasma deceleration) and sometimes the mode grows to very large amplitude causing the plasma to disrupt. Using a high energy NPA, measurements were made of the energetic ICRF heated hydrogen ions. We have inferred large vertical transport of the ions from the plasma core during the MHD activity. When the 'chirping' island develops, the ions can be transported as far as the stochastic ripple diffusion domain at the top of the plasma[1].