Update for 1.5, I had to change some things to make it work in the new version, I tested it briefly and it appears to work fine.

Added a new option to disable the boost while pawns are drafted, as suggested by monsone.

Update for 1.4, no other changes.

Forgot to remove some debug text. You probably don't want your logs spammed with the name of the pawn attacking something, every time it attacks, again, and again, forever. Something something flat circle.

Added two more conditions to disable the boost:

• A player pawn makes an attack.
  
• A player pawn is targeted by something. This should prevent enemies in certain cases from instantaneously closing the gap between them and your pawns. Should also (in theory) disable the boost when a predator starts hunting one of your pawns/animals.

The speed boost will no longer turn back on while there are fleeing enemies.

1.3 Update.

Rewrote the 1.3 version so it's more efficient. You may possibly see performance increases of up to 0.00002 percent.

Updated for the impending Rimworld 1.2 release.

The speed boost can be manually togged off with the button or with the new hotkey. By default the hotkey is 5, but it can be changed in Rimworld's key config menu. Also added a new optional feature named: "Manual Reactivation". If enabled, when the speed boost is automatically turned off due to threats, it will not reactivate itself when the threats are gone, you will have to manually reactivate it either through the button or the hotkey.

Added a boost toggle in the widget bar on the bottom right of the screen that will temporarily disable the speed boost if toggled on. The visibility of the button itself can be toggled from the mod settings.