When you go on a trip with the boys. All 30,000 of them.
Edit: Also, can't help but wonder. In the earlier chapters Prof Morals mentions that the amount of heroes who had to go a second time could be counted on one hand. Assuming Prof Morals' job is guiding the 1 handful of heroes (at most, 4 others) I can't help but wonder what is taking up so much attention she failed to notice what happened with Hero B and Alex.