Ysido 4in1 esc fire

A friend of mine bought this quad and I soldered it together for him, but unfortunately after flying the second time today he hit a tiny sraqqly twig wich caused the esc to catch on flames (trying to evade the censorship)

It got so hot that the solder melted and the motor wires went loose and even some pads fell of the fc. So it isnt that I did a bad solder job like it seems in the pics since before everything was attached properly with no shortcircuits.

At first we thought the battery might have been the problem but its still intact (I threw it away anyways since I like my house)

What could have caused this? And how to prevent it from happening im the future?

This is the stack he bought: Ysido F4 V 3S Plus Flight Control Fc Ondersteuning BLS-45A/60a 4in1 Esc Stack