What does medic do in BFBC2? + other questions?

Okay the Medpack lets you heal others faster so they don't have to wait. The SMG does have lower hip spread but you aren't faster. The marking does not always work because it enemy could be to far away. The voice error is a bug. Bullets and grenades damage vehicles but it is pretty low on damage with the grenade doing a little more. You can get in a non squad vehicle just can't spawn in it. Hope this helps :D