"His father actually said he'd exploded himself where he did because "he didn't want to hurt anyone." The fact is, there was a large parking lot at his apartment complex where it would have been far less likely he'd "hurt anyone."
There is also the famous 'DUCK POND' near by..he could have gone there..HE DIDN'T!!
The Duck Pond is what I have been thinking all along, as the most obvious "open area" where he *could* have done his handiwork. You're so right.