If you eat undercooked rice it's not gonna harm you but it can be harder to digest the undercooked rice.
I have eaten undercooked rice when I was hungry and didn't feel like cooking it any further and although it was a bit tougher to chew and digest it was perfectly safe to eat.
Rice is fully done when it becomes soft so if you do cook rice and it's still a bit hard just add some more water to it and cook it a bit longer.
In the microwave when I cook rice it takes around 15 to 20 minutes to cook a bowl of rice.
On the stove it takes around 30 minutes to have fully cooked rice.