install an event filter to main maya window, and only intercept the ctrl+/ key when mouse pointer is on top of script editor

test_event_filter.py

from PyQt4.QtCore import *
from PyQt4.QtGui import *

import maya.cmds as mc
import maya.mel as mel


class CustomFilter(QObject):

    def eventFilter(self,  obj,  event):
        if event.type() == QEvent.KeyPress:
            if 'scriptEditorPanel' in mc.getPanel(up=1):
                if event.key() == Qt.Key_Slash and event.modifiers() == Qt.ControlModifier:
                    print 'ctrl+/ pressed'

                    # what is current tab?
                    tabIdx = mc.tabLayout(gCommandExecuterTabs, q=1, st=1)
                    print 'current tab:', tabIdx

                    return True
        return False


def get_mel_global(var):
    return mel.eval('$tmp_var=%s' % var)

gCommandExecuterTabs = get_mel_global('$gCommandExecuterTabs')

filter = CustomFilter()
qApp.installEventFilter(filter)

# This will remove the filter we installed
# qApp.removeEventFilter(filter)