This boss fight involves a telekinetic witch that can teleport in, deal slight damage and freeze you and your aim in place for a few seconds and then teleport out. She's assisted by a great deal of enemies, from hordes of Beheaded Rocketeers to Scrapjack Rocketeers, that can make a great deal of damage during this period.
Since she can teleport pretty much anywhere and lock you in at the most unfortunate of times, this fight needs to be planned very carefully. Supplies scaringly abund, but they don't help with the major challenge - locating and aiming at the witch before she attacks: if she surprises me from behind I'll be powerless to do anything about it.
What can I do to make this fight as painless as possible?