The question is can I double slice twice in one round with appropriate penalties while under the quick condition from the items below?
I need 2 actions and 2 strikes to double slice.
DOUBLE SLICE FEAT 1
Requirements You are wielding two melee weapons, each in a different hand.
"Make one Strike" (see page 308) with each of your two melee weapons, each at your current multiple attack penalty. The second Strike takes a –2 circumstance penalty if it’s made with a weapon that doesn’t have the agile trait (see page 182). If both attacks hit, combine the attacks’ damage, and then add any other applicable enhancements from both weapons. For purposes of resistances and weaknesses, this is considered a single Strike. This counts as two attacks when calculating your multiple attack penalty (see page 305).
Speed rune:
While wielding a speed weapon, you gain the quick condition, but you can use the additional action granted only to make a Strike with the etched weapon.
Haste spell/ Potion of Quickness
The target acts faster. It gains the quick condition and can use the
extra action each round only for Strike and Stride actions.