This is a setting hack that can be enabled on the "Settings" page of the Mods List.
This hack stops timers from counting down.
Settings
Mission Timer
Set whether or not mission timers will be frozen.
Defaults to Enabled.
Timer Objectives
Set whether or not the timer for "timer" objectives will be frozen.
Not recommended, this makes many stages in the base game and various mods impossible to complete.
Defaults to Disabled.
Version History
Version 1.27
Added a warning when enabling the Timer Objectives setting as it makes several missions in the base game, as well as many throughout various mods, impossible to complete and is probably not what you want.
Version 1.22
Added settings to this hack and added the ability to freeze timer objectives.
Version 1.18
Moved this hack to the new Settings page.