system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Bruce Banner is building a machine that will instantly pulverise him when he turns it on. Would the Hulk prevent him from completing it?

Let's say Banner wants to kill himself once and for all, without being angry or anxious about anything. He sets up a machine which can instantly pulverise himself when turned on. He knows he can't shoot or drown himself because that will just alert the Hulk to save him, so he builds the machine slowly over a period of weeks. He maintains his heart rate and blood pressure.

You can basically boil this down to if Hulk can sense Banner actively working against him without undergoing emotional stress that increases his heart rate or blood pressure, or putting his life in immediate danger.
gpt
Upon suffering fatal damage, the Hulk takes over and regenerates the body wholy. He's regenerated from bits of flesh on a skeleton in the comics, and survived a bullet to the roof of his mouth in the MCU, as well as a fall from a helicopter where he clearly didn't transform until after impact. 

The Hulk doesn't need to stop Banner. Unless the damage was literally instant, the Hulk would emerge as Banner was killed and stop it. Likely super pissed that Banner tried to kill himself, and by extension The Hulk.