It is like HolySchmidt said: If you speak of the "exploding" physics, then most of the time it is eighter an extreme pose, where the breast collides with other parts of the body, or the joint forces are spazzing out, or two persons physics colliding untill it explodes. Some time it is even the figure colliding with an environment, if the figure's pose is a bit overdone and collides too much with the environment's collider.
You see, its all about physics and collision.
This is unfortunately quite normal with VaM, the game's physics doesn't work perfectly.
The only thing you can do is to be a bit cautious: If you see a figure's limbs starts jittering, relax the node/joints tension (don't draw the points too much away from their origins), and/or edit the pose to be less tense.
And never ever spawn or draw a person into another one.
