Through the ordeal they just went through, Cyanide leveled up to Level 33. The others didn't gain as much EXP since they didn't do much damage to the plant at all, but ultimately, Cyanide was the main reason they managed to beat that miniboss anyway. Someone had to the dirty work—and the person who did, would reap the rewards.
Since he's leveled up his other stats decently by now, Cyanide decided to return to focusing on the two major stats he believed to be most important for combat: STR (strength), and AGI (agility). For the purpose of the 10 CP he obtained from this level-up in particular, he chose to use it on AGI. And like usual, he conserved the SP, since now wasn't the time to decide on what to spend it on.
Even though they had defeated the giant flower, their journey in Envy's lair was still not quite finished. That was just the first gatekeeper—there were many more challenges coming their way.