A segunda parte da sua pergunta, sobre os danos Slam , tem uma resposta canônica.
The Gamemaster may limit your base slam attack damage (before applying circumstance modifiers) by the series power level.
Example: Your hero flies into a foe, moving at speed rank 10. His unarmed damage (Strength) rank is only 2, so he uses his speed rank of 10 for the damage. Since he also moved his full speed to build up momentum, he increases his damage by +1 for a total damage rank of 11. If a base damage rank of 10 is too high for the series, the GM may impose a lower limit on his slam attack damage, applying the +1 modifier for the full speed move to the lowered rank.
Então, em suma, não há nada que garanta a você a chance de quebrar PL, especialmente se você tiver um personagem construído para evitar qualquer dano causado pelo ataque.
Em relação à reação "ataques", ligando-o ao movimento, o ônus está no GM para policiar construções abusivas como essa.
The GM is the final arbiter as to whether or not a triggering circumstance is suitable for a particular effect in the context of the series. Caution should be used to keep this option from being abused.