When someone plants a grenade in your mantis (I think this part is already well known), you can easily jump out and survive.
But when you immidiately jump back in your Mantis, the game has a stroke and even the Mantis survives, because the grenade just explodes on top of the Mantis and not in it.
this is what happened [I just died, because I got shot when climbing. At the end, the enemy had my Mantis. I had to destroy my own vehicle 
]