You're getting ahead of yourself…. There is usually some warning before an engine goes TU. Not always. Pay attention to your run-up results, and you'll know if something isn't right -- usually. If you don't and the engine pukes at 300 feet, land straight ahead (or nearly so) under control. You'll spend a lot of time in your training working through what-ifs. But the main thing is, don't take off with an out of spec indication in run-up (like, rough running on one mag or oil temperature too high). Yes, there are overconfident pilots. Don't be one of them.