This one seems a lot to unpack...
Your allies are used to being in the splash zone of your hurled weapons, and try to ensure that at least your opponent gets hit.
Prerequisite(s): Base attack bonus +1.
Benefit(s): You initiate this feat whenever you throw a splash weapon into a square within the reach of an ally who also has this feat and miss your target. Rather than you rolling to see where the weapon lands, the abettor can try to redirect it as an immediate action by making a melee touch attack against any adjacent foe. If the abettor's attack hits that foe, the splash weapon impacts in the nearest square the targeted foe occupies
Now... Here's the situation I'm looking at.
I'm playing an Inquistor, one of his companions is an Alchemist... It seems WAY too common for her to hit him with the bombs/alchemist fire/etc... It's actually become a running gag.
Inquistor's can treat their allies as if they have the same teamwork feat. Based on this... Can I act as if she had this feat, then redirect the splash weapon back at a foe?
It KINDA feels like I can. It says it's 'initated' by the thrower, but doesn't take any kind of swift/immediate/standard action per se. I can see this going a couple ways.
Here: Betrayal Feats
That long, super confusing paragraph at the top. Very legalistic, unpleasant read, and my main deterrent from using those feats. The bit regarding inquisitors is at the bottom:
Characters with class abilities granting allies access to teamwork feats (such as cavaliers or inquisitors) can select these teamwork feats normally, but allies who are granted these feats can use the feats only as initiators, not as abettors. An inquisitor could not grant an ally the Ally Shield feat and then use the ally as a shield, for example, but he could allow that ally to use him as a shield.
Regarding the OP's question, looks like the Inquisitor could redirect the attack, but can't be the person throwing the splash weapon. And even there, the feat only triggers when the thrower misses their target.
Basically, they throw their bomb at the enemy, but it misses and you are within reach of the thrower. Before finding out where it scatters, the Inquisitor can use this feat to a make a touch attack against any adjacent enemy, and, if successful, the bomb lands in that nearby square.
So, you ensure that the bomb will include you in the splash....
Or in other words, the ally next to you throws a bomb, and rather than letting it hit the target, you decide to hit the bomb with your sword, causing a point blank explosion for yourself and a nearby enemy.