If a character throws a grenade in Shadowrun 4th Ed., what rules are there for another character trying to pick it up and throw it back? Is this covered somewhere in the book? I know it's in SR3, but I couldn't find it in 4th Ed. A page reference would be very handy. Thanks!
The Arsenal supplement actually has the rule listed on page 163.
Characters with an action available before the grenade explodes may make an Agility + Reaction (3) test to pick up the grenade and throw it back.
If they succeed: Free Agility + Throwing Weapons ranged Attack Test to get rid of the hot potato.
If they fail: The character does not manage to pick up the grenade, and will be at a Range of 0 meters when the grenade detonates.
I did not find a specific entry on returning a thrown grenade in SR4, (or 3rd or 1st) upon review. Everything needed is accounted for in the combat rules, however. An optional rule for this is presented in the SR4 release 'Arsenal' on page 163.
Grenade use is dealt with on p155 of the core book, presenting the scatter table, and noting the time frames for detonation with and without an airburst link, with page references.
From these you can determine how successful an attempt to get to, pick up, and throw a live grenade might be on a case by case basis:
If these steps are too open to interpretation or debate, or faster resolution is desired, the rule in Arsenal (here) will model its stages with one roll which if successful will lead to a thrown weapons roll.