If I go into the past.
Place a bomb onto my past self.
Go into the future.
Place a bomb on my future self.
Go into the present.
Place a bomb on the time machine.
They explode at the same time.
What happens?
I believe time travel can get loving confusing and makes me hate it 90% of the time.
If you blow up the time machine, there are still 2 other versions of it, in the past and future, you blew up the one where you are. (This if say, your time machine needs to be in the two different times to work, like a time portal.)
Your actual scenario can't truly work, since you said that you stuck bombs on a past self and a future self and they go off at the same time. Not possible if they're two different times. They can't go off at the same time at different times.
However, if say, it's 12:00 when you start this operation, you go into the past and stick the bomb on yourself at 09:00, you then travel into the future and stick a bomb on yourself at 14:00.
How did you do that if you left at 12:00, went to 09:00 and left Time then. There is currently no future version of you left, unless you eventually end your travelling at some point, which until then, is an impossibility of itself.
However, let's say for arguments sake, that there is a version of you at 14:00. You strap a bomb onto him, and the past version has a bomb on him. That past version though, is your current version as you had that bomb on you when you passed through time at 12:00. This future self still has that bomb on. You have 1 bomb on and the future self has 2. You'll now both blow up.
Now, if you say that each time you go to a different time, you open a new parallel universe. Well, you've stuck an explosive on two different versions of you who both explode simultaneously and your time machine. You're now stuck in an alternate reality in which you died earlier on and never died in the future, unless the future guy you strapped a bomb too is also a different reality. In which case, you're trapped in a reality where a version of you has blown up, and another version of you has blow up in some other universe.
Confused now? 'cause I am.