Five pin hole sized holes and the mangled wreck of a USB port. The other factor is how strong is the containing case? In the case of the ageis 100, very. That vent might get quite a bit bigger before it’s done burning, and the flames shooting out of it might get kinda long though with all the stuff escaping through that one hole. This is why I personally think the bottom door on the legend will probably just blow open. It takes a metal fire not just a vent to do that though, and if you’ve got a metal fire you’re looking at a future pile of melted slag no matter what you’ve got, Be it a mod, or an electric car, or a WW2 nazi rocket plane. The only thing to do is get the hell away from it. Or it the hell away from you. Luckily mods are small enough to be thrown.
You are picking straws. Never mid the “what if” scenarios. Find the pressure of release for battery venting and tell me without an ounce of doubt that those 5 small holes on the Aegis are adequate for all venting situations.
Battery venting is due to pressure increase from within the battery. This is caused by an increase in temperature and will be different depending on the situation and the cell. There is not static number. And if that increase in temperature from within the battery is not put under control within an extremely short time, the cell may enter a state of thermal runaway. Non of this can be safely predicted.
As for blowing up devices…the pressure release must be great enough to relieve enough pressure so that internal pressure does not exceed the devices integrity. Can you say without an ounce of doubt that every device that employs venting holes will allow this?
Bottom line: Do not fall for a false sense of security just because your device has a few vent holes. Respect your batteries so that you do not enter a state of venting to see whether your device has or has not the capability of keeping that venting under control.