To set off the perfect detonation (for example, blowing up a tank, etc.), switch to Jones and give your detonator to Foley (or another member of the team). When Jones runs in to plant the C4, he doesn't have to be alive in order to blow up the C4. You can heal him later. Also, if there is a minefield do not waste C4s; instead use grenades. If you hit the mines correctly, you could set off a chain reaction. Bradley and Connors typically have the most grenades. Finally, you can blow up a tank that has a satellite on it by firing two sniper shots with Foley.