[Being with in arms reach of Ken means that Schuldig has moved himself into the murder zone, not to mention encouraging it by making an aggressive move. Schuldig's words only enrage him further.

Which leads to his own aggressive move, a punch aimed at the cheek bone]

LET GO! [He wants to say that erasure of the past wouldn't work either. It still shows in who you are, that the past makes you, but he can't get his thoughts together because of his own emotional state]