Gleich

Simulteneously

This refers to the two fencers acting at the same time, be it intentionally or unintentionally.

In the former case the movement is related to Indes in that the fencer does something at the same time as the opponent to set them off and counter, or withdraw.

In the latter case it is because the fencers haven't followed the flow of initiative and often this results in the ubiquitous "double kill" - this is the most normal instance of Gleich, and the most annoying.