There is a system action 'Set minimum framerate'. Manual says about that action ....
Set the maximum delta-time (dt) value based on a framerate. The default minimum framerate is 30 FPS, meaning the maximum dt is 1 / 30 (= 33ms). If the framerate drops below 30 FPS, dt will still not exceed 1/30. This has the effect of the game going in to slow motion as it drops below the minimum framerate, rather than objects stepping further every frame to keep up the same real-world speed. This helps avoid skipped collisions due to stepping a very large distance every frame.
Additional info: All of Construct 2's behaviors use dt in their internal movement calculations. (exept physics i think).
Linking one to the other: Timer behavior is using dt. That makes a timer frame independent till the minimum framerate is reached. Lowering the minimum framerate with the system action will make collision defection on very low frames rates virtual impossible.
Whatever you do with it, just dont allow your game to drop fps below 30 fps.