Sh3naniganz

Before the arena countdown, you can click a power/temp power and queue it. The power will go off right at the start of the countdown, thus giving you the effect of said power/temp power. I have tested quite a few of the temp powers, and while some are just silly, like Signature Pets that other people in the arena will notice, others, like recovery serum and frenzy mutagen, are a little more inconspicuous.