In this case, which sentence is more precise ? 1) I'm going out to see the client for a while. If I DON'T come back please switch off my computer. 2) I'm going out to see the client for a while. If I DIDN'T come back please switch off my computer.On top of that, I was thinking to use 'DIDN'T' because the reason is, it could suggest a subjunctive form by imagining ''he wouldn't come back''. Please give me some advice. Thanks.