Color Mechanic:

Whenever TLI is about to approach, the monitor will alert you that there is a temperature spike and that you need to react fast. To identify the color in which the decision he will attempt to attack you, you need to exit the monitor to see the color glowing up the lobby room, then fend him off.

Heater going back up (How to outsmart it):

The more heaters you shut down, the more agitated TLI will get, and he will try to ruin your progress by upping the active heaters back to 100%. This will begin to become more of a problem around the 3rd or 4th heater, but there’s a way to get past it.

Basically, you will have an advantage when TLI starts on the same color two or more times (Must be Blue or Orange for this to work), once your mechanic is on cooldown, when he approaches on the same signal (color), you must keep draining your current heater until the cooldown stops, then use the mechanic as quick as possible. This strat is a big risk since you are increasing your chance of dying by TLI. Yellow signal is the most dangerous, considering that you need to stay off your monitor as part of its mechanic.

I say use this strategy since it actually worked many times, I consider it a way of beating Endgame for the better.