When i place proximity mine somewhere on map will it dissapear if i go to much away from it , and how long will it last will it like deactivate itself after some time ? Oh and also can it kill me if i step on it ?
Mines will stay for however long you place them for providing you do not switch continent or log out. They never deactivate unless they are blown up either by friend or foe. Your mines will not activate if you or any friendlies step on them, but they will either kill you or cause severe damage if they are shot at.
You can also have engineer mines and Infiltrator mines at the same time. Switch to engineer and drop some mines. Switch to infil and also place infil mines.